Personally I’d say yes, but I think it’s a very personal question.
I started life on a rigid, went to HT, then to heavy long travel FS, then back to short travel FS, then back to HT. I was fastest and fittest on normal UK trails on my rigid and HT because I got out more and it felt more spritely. I was fastest on downhill sections on my long travel full sus, despite being less fit. So there’s no right or wrong answer.
I’ve moved back to a HT and can do my usual trails notably faster against the watch, find it more fun and it _feels_ faster too. I find it’s a lot less forgiving than the FS was despite being about the same weight and front travel, and as such I’m remembering having to be more careful with my line selection and how to manage technical sections I’d just have flown through on the FS without even thinking about it. I’d say it’s improved my technique, my speed and my fitness. But if I were less confident, more fit and tended to do more downhill routes I’d probably have concluded the opposite.