In a recent interview with German newspaper Handelsblatt, Tesla Motors (NASDAQ:TSLA) CEO Elon Musk had some pretty harsh words for Apple (NASDAQ:AAPL). In particular, when asked whether he takes Apple's widely reported automotive ambitions seriously, he jokingly stated, "Did you ever take a look at the Apple Watch?"

Though this may have been meant as a joke at Apple's expense, here's why the folks at Apple should be the ones laughing.

Did you ever take a look at Apple Watch revenues?
According to a forecast from Pacific Crest analyst Andy Hargreaves, who has been fairly neutral to bearish on Apple shares, Apple is on track to sell around 10.5 million Apple Watches this year.

If we conservatively estimate Apple Watch average selling prices at $400, then this would imply that Apple will be able to bring in a cool $4.4 billion in revenue from sales of the device this year.

As far as Apple products go, this revenue is nice to have but hardly a game-changer, especially in the context of the nearly $183 billion that Apple took in during its last fiscal year and $233 billion in revenue that it's expected to achieve in fiscal 2015.

However, compared to Tesla's entire business, the Apple Watch is quite respectable. Indeed, Tesla is expected to achieve around $5.4 billion in sales this year. Tesla's entire business brings in more revenue than Apple will probably see from the Apple Watch this year, but the difference between them isn't all that great.

The Apple Watch is also probably brings in far more profit than Tesla does
Although the $5.4 billion in revenue that Tesla is expected to rake in this year represents robust growth from the $3.6 billion that the company did in the year prior, Tesla is also expected to lose $0.83 per share this year.

In contrast, it's likely that the Apple Watch will prove to be highly profitable for Apple. If we assume that Apple does, indeed, sell $4.4 billion worth of Apple Watches, and if we assume gross profit margins on those sales of 35%, then that's a solid $1.54 billion in gross profit.

Further, even if we assume that Apple's annual spending on Apple Watch product development is around $1 billion, an estimate that actually seems a little high, the Apple Watch business would still probably be more profitable than Tesla Motors.

However, this really isn't about the Apple Watch. The only reason anybody even bothered to ask Musk about his views on Apple at all is that Apple is said to be going into direct competition with Tesla with an electric vehicle of its own, code-named Project Titan.

The Apple Car might not be a "Tesla killer," but Apple shouldn't be underestimated
It's far too early to tell whether Apple's automotive efforts will ultimately pan out. They may very well ultimately fall short of what Tesla is doing and will do in the coming years.

However, over the past decade or so, Apple has been very successful at fundamentally reshaping the personal-computing industry.

Although it might seem that the automotive market is far removed from the "personal computing" market (i.e., phones, tablets, notebooks, and desktops), graphics specialist NVIDIA (NASDAQ:NVDA) -- which supplies processors to Tesla -- has described cars as "extremely powerful supercomputers" that require "parallel processing, extensive software based architectures, and deep learning technology."

When viewed in this light, it makes a lot of sense that Apple would want to enter the car market. And given Apple's track record of building fundamentally game-changing computing devices, it's not a company that Tesla -- or any other automotive maker -- should so lightly dismiss. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.