Despite @Ruin Explorer 's claims Wisdom is an ultra strong stat - about 25% of spells that force saving throws are wisdom saves, and Perception and Insight are both skills that can save your life.
This is a half-truth, and didn't claim it wasn't true at all, so you're putting words in my mouth, and that's just going to cause confusion.
WIS is only strong or useful at all if you ALSO have access to:
A) Perception (and preferably but less importantly Insight)
B) Proficiency in WIS saves.
Otherwise it's hugely worse than CON as a secondary, and worse than DEX for anyone who isn't wearing heavy armour.
I mean, how many WIS saves do you make in a long campaign? 20? 50? And how many times is you AC rolled against? 200? 1000?
WIS is not worthless, but only really one PC in the party needs a high WIS, or benefits much from it, and they want to align having those two skills with it. Others benefit from it in a far smaller way.
HP and AC are more directly useful to every single character (and saying they aren't is just not realistic).
I mean, adding it to background is actively more restrictive than the already existing Tasha's setup, AND it makes new backgrounds actively less compatible with older material.
I don't get it. I mean, I do get it, but the reasons almost certainly aren't better gameplay.
If we look at it honestly - there's pretty much one plausible goal here - forcing to people to buy more books to get more backgrounds, and those backgrounds are more optimal and/or cooler. Then they can wave the books at the DMs, and the exact sort of DMs who aren't keen on Custom backgrounds are likely to be fine with stuff that's from books.
I honestly can't really see any other rationale - it's flying against how D&D has been played for 5+ years, and it's actively making the game less compatible. I can see another reason - not a rationale - simple bad design, without understanding the consequences, but I'd almost prefer that they were trying to sell books, because that's just depressing.