in nearly 7 years, I've never trained No-Gi once (schedule doesn't allow for it and don't think my body could handle that much anyway). When I was a white belt, my coach convinced me to also compete No-GI because "why not?" Won my first match by points, second match broke a kids arm with an americana, third match got belly to belly slammed by a sandbagging wrestler 3x in a row, dumbass ref didn't do anything until I said "wtf are you doing ref?" He pauses and resets the fight in the center, my back is jacked so I tap to a sloppy garbage armbar, couldn't compete in my medal match for nogi, or in the Gi at all.
TLDR: If you like Gi and have some athleticism, it can be a fun experience, just make sure its a well officiated tournament.