Good point… no, I don’t usually need to adjust FTP during a workout, but occasionally its nice to do an endurance-level workout when the actual workload is designed as high intensity… so its a way of tailoring to change level to suit training schedule. Likewise, a group workout might be endurance, but you want to go hard. I find that joining a group session is much more fun than doing your own individual session, so sometimes I pick whatever group session is convenient and tailor the level to suit. I’m probably not the typical use case!