Just last week I started a new project, injecting some firebase-backed functionality into a squarespace site, and I used jQuery.

I use it for the same reason I use lodash when I could do everything it does in vanilla js: because it's a slightly more dev-friendly API.

Much like the PHP community, jQuery's community has earned it a reputation as a hacky tool for people who don't understand where jQuery ends and Javascript begins. However, it didn't become popular by accident, and in competent hands, it still has its benefits.