Can you trust WhatsApp more than Facebook Messenger? Credit: Google Play store.

When Facebook (META -0.52%) started pushing Messenger as a stand-alone app, it raised questions. Why force users to change the way they connect with friends?

Facebook doesn't see it that way. Rather, in a response to TechCrunch, which broke the news in late July, the company described the shift as simplifying the messaging experience:

As we've said, our goal is to focus development efforts on making Messenger the best mobile messaging experience possible and avoid the confusion of having separate Facebook mobile messaging experiences. Messenger is used by more than 200 million people every month, and we'll keep working to make it an even more engaging way to connect with people.

Sounds interesting, right? If only it were that simple.

Hysterical headlines accusing Facebook of overreaching in its data collection practices has marred early reviews of Messenger. Mythbusting has since alleviated some concerns, though it's obvious that fear remains.

For investors, that leaves an interesting, and potentially troubling, question unanswered: Can the social network convince its 650 million-plus daily active mobile users that Facebook Messenger is safe to use? Or will privacy hawks demand a total switchover to ad-free WhatsApp, which Facebook spent $16 billion to acquire? Let's review the required permissions for both services, and see if switching would make a difference for users.

Facebook Messenger vs. WhatsApp: What we know right now

According to Google (GOOGL 0.55%) (GOOG 0.74%) Play, WhatsApp has nearly double the number of reviews -- 18.4 million vs. 9.6 million -- and scores higher among those using the app -- 4.4 stars vs. 3.9 stars.

The variety of permissions Facebook requires for using Messenger is at least partly responsible for the difference. "If they're not spying on us, then why are they taking away our option to [not] download Messenger," wrote user "Chris M."

Would he do any better using WhatsApp instead? See for yourself. The following specifies permissions required for both apps, with the differences highlighted in bold:

Facebook Messenger
WhatsApp

Identity

  • find accounts on the device

  • read your own contact card


Contacts/Calendar

  • read your contacts


Location

  • approximate location (network-based)

  • precise location (GPS and network-based)


SMS

  • edit your text messages (SMS or MMS)

  • receive text messages (SMS)

  • read your text messages (SMS or MMS)

  • send SMS messages

  • receive text messages (MMS)


Phone

  • directly call phone numbers

  • read call log


Photos/Media/Files

  • test access to protected storage

  • modify or delete the contents of your USB storage


Camera/Microphone

  • take pictures and videos

  • record audio


Wi-Fi connection information

  • view Wi-Fi connections


Device ID & call information

  • read phone status and identity


Other

  • receive data from Internet

  • download files without notification

  • run at start-up

  • prevent device from sleeping

  • view network connections

  • install shortcuts

  • read battery statistics

  • change your audio settings

  • read Google service configuration

  • draw over other apps

  • full network access

  • read sync settings

  • control vibration

  • change network connectivity

Device & app history

  • retrieve running apps


Identity

  • find accounts on the device

  • add or remove accounts

  • read your own contact card


Contacts/Calendar

  • read your contacts

  • modify your contacts


Location

  • approximate location (network-based)

  • precise location (GPS and network-based)


SMS

  • receive text messages (SMS)

  • send SMS messages


Photos/Media/Files

  • test access to protected storage

  • modify or delete the contents of your USB storage


Camera/Microphone

  • take pictures and videos

  • record audio


Wi-Fi connection information

  • view Wi-Fi connections


Device ID & call information

  • read phone status and identity


Other

  • receive data from Internet

  • read sync statistics

  • create accounts and set passwords

  • run at start-up

  • prevent device from sleeping

  • view network connections

  • install shortcuts

  • use accounts on the device

  • uninstall shortcuts

  • change your audio settings

  • read Google service configuration

  • toggle sync on and off

  • modify system settings

  • full network access

  • connect and disconnect from Wi-Fi

  • read sync settings

  • control vibration

Sources: Google Play profiles for Facebook Messenger and WhatsApp.

The price of using Facebook Messenger

So, there you have it. WhatsApp doesn't ask for as much access to your data. Yay? Here's the thing, Fool: Facebook, like Google, is in the data business, and Messenger is a channel through which it collects information. Some of it will be monetized; some of it won't.

By contrast, WhatsApp is in the communications business. Facebook benefits if WhatsApp gets more unconnected people to the Internet. There's no need to ask for permissions because the target audience -- or at least the intended audience -- doesn't have as much useful data to share.

When they do, many years from now, Facebook will no doubt ask them to upgrade from WhatsApp to Messenger. In the meantime, it makes sense for the services to co-exist.