The whole concept of real user monitoring is that it allows you to detect erroneous patterns in how they specifically use your product, so that you can ideally fix said problems if they're common enough. I'm not wildly excited over the idea of being tracked either, and ideally this is something driven via the site offering the service, but it can be a very valuable tool for FE devs to figure out why customers are having a negative experience without having to tell you explicitly, which is great.