With Apple's (NASDAQ:AAPL) first smartwatch deliveries beginning this weekend, many consumers and investors are wondering just how popular the device will be. While we may get a glimpse of how the device is performing in the market on Monday, when Apple reports earnings, it's worth considering the device's strengths and weaknesses in the meantime.

In a previous article, I explored some of the watch's most notable tech specs. And despite some impressive features, the device is still lacking one crucial element found in much of today's smart technology: GPS.

Apple Watch without a GPS
Health is a major focus of the Apple watch. The Apple Watch Sport version of the device is particularly built with exercise in mind. It uses a lightweight, strong anodized aluminum for the casing, and the display is protected by strengthened Ion-X glass. The fluoroelastomer band is durable, strong, and light. Using the watch's onboard accelerometer, the watch measures total body movement and heart rate.

Apple Watch worn during a workout. Source: Apple.

These features are all wildly impressive, but without a built-in GPS, the watch could fall short of expectations. To be fair, the Apple Watch taps into the iPhone's GPS when it's near the smartphone and serves this data to apps. But there will certainly be times when the watch is worn while an iPhone is not being carried -- particularly during a workout. Whereas GPS may not be necessary while running on a treadmill or exercising inside a gym, outdoors enthusiasts would definitely appreciate it during runs outside. 

Still, even without a GPS, running distance can be measured, according to Apple. The company explains in its Apple Watch guided tours videos that after initial training by running with the iPhone for the first few times, the Apple Watch can learn a users stride. After the device learns a user's stride, running distance can be measured without GPS.

For the greatest accuracy when walking or running outdoors, bring your iPhone, which will help calibrate the accelerometer in Apple Watch for times when you don't have GPS, such as treadmill workouts or running outside without your phone.

Running without the iPhone, however, will make it impossible to review your exact routes from outdoor running.

Apple Watch Sport. Source: Apple.

For biking, however, it should be easier to bring the iPhone along for the ride.

Don't forget, you'll need this, too
Apart from lacking GPS, the Apple Watch has one other shortfall: users must have an iPhone 5 or later to use the Apple Watch smartphone app. (Of course, the Apple Watch is not a complete solution for replacing a smartphone. It's meant to serve as an extension of the iPhone, adding to a phone's capabilities and serving as a complimentary tool.)

Foolish wrap
Even if the Apple Watch is a success, it's going to be hard for the new product line to have a huge impact on Apple's business. The tech giant already raked in about $200 billion in revenue in the past 12 months. However, as a complimentary device to the iPhone, the addressable market for Apple Watch is undoubtedly huge. In the company's most recent quarter alone, Apple sold a whopping 74.5 million iPhones. If the company can convince just 10% of eligible iPhone users to purchase the device in the next few years, Apple's investments in the new technology would easily pay off. In other words, while there's no guarantee the Apple Watch can move the needle on Apple's bottom line, the potential certainly exists.