So if just 7+% of people take +2 Cha, +1 Wis, then it's worth the space.
No, it isn't. Because background isn't just stats - it's also Skills and a Feat, and we can be very sure that there will be a small number of backgrounds that are optimal for a very large number of classes - and I'd bet money, like real money, that those backgrounds are not the most thematically common backgrounds in D&D at all.
They should have kept stats out of this entirely. Stats should have been a player decision, as they have been for 5+ years for easily most D&D groups. You cannot put the cat back into the bag. And WotC are, inexplicably and rather stupidly, trying to do exactly that.
This will create a situation where people just whinge continuously from now until whenever the next version of D&D comes out. Because you can say "Oh well as a DM I'd allow people to create backgrounds freely!", but like, a lot of people will be in groups where the DM doesn't do that, either because they think the restrictions are smart, or because they're too scared to "overrule" the books or the like. It'll be particularly annoying on any digital platform, because unless they just put an override in, they'll be restricting people's stats.
The end result will be some rules that almost no-one likes, and almost no-ones RAW (or even close to it), but that everyone complains about. It's absolutely outright bad design. The first piece of genuinely bad design I've seen "go live" with 2024. Maybe not the last.
And I expect there is litterally 1 background that has Int/Wis/Cha, our of 16.
Sure but anything that misses CON is almost as bad, and a lot of ones which miss DEX will be pretty bad.
EDIT - To be clear, we're going from a situation, where, for the vast majority of groups, the player could choose:
1) What stats they had bonuses to.
2) What skills they had
3) What tool proficiencies they had
To one where they cannot choose ANY of those things. And also cannot choose a Feat! And WotC thinks this is going to go well why?