Sshhhh. So many people will lose so many bullshit jobs if this gets discussed widely. There are entire tertiary industries built on top of front-end tracking and most people with a modicum of analytical ability know it's turtles all the way down.
Lots of user experience professionals find utility in data that serves discovery and design sprints. Lots of product management professionals find utility in data that serves validating incremental feature engagement.
https://en.m.wikiquote.org/wiki/Turtles_all_the_way_down
In this context, I'm referring to the "trust us, it works" attitude that people who sell/provide analytics on front-end tracking use to justify their effort/expense. Based on experience, when you point out obvious problems doing analytics with JS, they keep repeating the mantra "but you _need_ front-end analytics" infinitely.