I've done so many projects that revolved around instrumenting every little click and creating A and B versions of an experience to run tests against and in all

I've done so many projects that revolved around instrumenting every little click and creating A and B versions of an experience to run tests against and in all that time I can't recall a single useful product decision that was actually informed by the collected data. I would disagree on user research. It works on certain types of broad questions like messaging and branding. It's probably overused though.