it is, at least for me and the people I play with, but it's still a game system, not just free-form improv storytelling. The rules give some guardrails to help with the process (and, mostly, to provide a way to do combat on even grounds).

The guardrails can and should be broken at times, but if you disregard them entirely, I think it's a better idea to start with free-form storytelling from the get-go. Which can be a great experience, but only if you're playing with a group you really trust to not descend into personal power fantasies