How come?

Edit: explanation why I'm probing for more as I was probably flagged as a troll but the original commenter :-p

Google and Apple are using house fonts that are heavily based on DIN, probably because DIN fits a lot of the criteria the companies took into consideration when picking a starting point for a watch (contextual constraints like various lighting situations, distance of read, likely screen pixel density, etc).

In Google's case it has been tweaked to be used on a variety of devices down to the very small (watch). In Apple's case, they made this font to be used on the watch only, as far as we know so far.

Based on that assumption, I think both companies have done a great job for the user by designing a font that meets all of the criteria that have set out to meet, instead of differentiating for the sake of differentiation on a 'brand' level.

Speaking of the 'brand' thing, it's also the case that Google's guidelines call for bright, colorful and 'light' feeling backings for text (on Android Wear most notification text would be a dark gray, per their guidelines). For the Apple Watch, it's almost all white on black. The two brands couldn't look much more... um... black and white... next to each other.

I think the users win here. No matter which watch you pick (or both!) you're getting something thoughtfully considered from the designers.

If you overlaid any DIN style font at 18pts it's going to match within 10px as well. Not very close. Though I do think the font looks more android like.

It's more like Apple's original Mac OS 7 font.