The point isn’t that there are solutions to keeping it charged. The point is it’s a needless concession for Apple to make when other wireless mouses have found elegant ways to achieve simultaneous use and charging. This wasn’t an instance of Apple reinventing something that will later seem so obvious.
It is obvious. People will leave wireless mice plugged in all the time out of superstition or worry. Apple’s way elegantly eliminates that possibility. Anybody who wants to plug in their wireless mouse may purchase another.