As a counterpoint, I had a similar conversation with a report of mine about jQuery. He said it was not necessary and you could just use vanilla js.

I said while yes that's true as a dev if I told you I needed you to implement a new payment provider for billing would you tightly and directly align with who we used or abstract it away via some wrapper so that if we ever had to change it wouldn't be difficult? Of course everyone builds abstractions so you aren't stuck with a single provider because it's crazy not to.

I see jQuery as that abstraction. At the end of the day each browser is an api implementer and while they've come so far, that doesn't mean the situation is stable and we'll never see implementation fracture again. It of course doesn't have to be jQuery but any direct implementation of JS seems to have that risk which is easily mitigated by wrapping the basic functionality. I don't know why you wouldn't choose to do it.