> I totally think they done this on purpose to prevent anybody to use the mouse while charging it. In that way, there isn't anybody continuously using the mouse without removing the cable, making the product look like is wired instead of wired, and breaking that minimalism design they want to.
There's no way apple is that petty or instructive. The wireless keyboard can be charged while in use, so your theory kind of falls flat.
I'm certain that apple just doesn't care. There were probably some tricky engineering problems during the design of the mouse which pushed the product team towards having the charging port on the bottom or it was a purely aesthetic decision — a recess / inlet for the lightning charging port probably didn't look great, and the designers rejected it.
So, they went with the port on the bottom. I'd wager the way Apple sees it, having to wait two minutes to get 9 hours of battery life if your mouse dies unexpectedly isn't the end of the world, and the battery lasts ~2-3 months on a full charge, so what's the problem?
I sort of agree with the hypothetical take I presented above. Yah, it would be nice to be able to use it while charging for those rare situations where you forget to charge it, but it's not the end of the world. Even if you disagree, it's astonishing to me how much ink has been spilled roasting apple for the magic mouse 2.