What you've described is how Personas are used incorrectly. Personas are a good way to have an overview of how people use a complex product. It's basically cat

What you've described is how Personas are used incorrectly. Personas are a good way to have an overview of how people use a complex product. It's basically categories and metrics, but high level and coarse. For example, for a streaming service you may have people who don't care about ads or audio and video quality because all they do is have something in the background while they cook, or drive the car. That's Persona A. And you have people who carefully curate their content, look for uncut gems, and have extensive music and film catalogs. That's Persona B. And then you try to look at your product from both perspectives. And then you either try to reconcile the two, or select one of them to cater to (backed up, by stats and data). However I agree that in many cases it's just a business fad