Rating forms are subjective. Rating forms are not behavioral. Lots of managers do this. They conduct appraisals so long as they have to do so to justify or withhold a pay increase. When staff hit their salary ceiling, or pay is not connected to appraisal and performance, managers don't bother.
Performance appraisal is FOR improving performance.
If nothing else, everyone needs feedback on their jobs, whether there is money involved or not. Most managers aren't in a position to monitor staff consistently enough to be able to assess well. And, besides what manager wants to do that or has the time. And, what employee wants their manager perched, watching their every mood. That's why appraisal is a partnership between employee and manager.