Communities are like less accessible hashtags and even those are underutilized. So just use hashtags.
nostr:npub1yzvxlwp7wawed5vgefwfmugvumtp8c8t0etk3g8sky4n0ndvyxesnxrf8q
I had difficulty posting to relays so I tried Habla as an alternative, and one feature that I they have over Yakihonne is that you can post to specific communities.
I personally find this useful, I know that the whole "communities" thing on Nostr, which I suppose is Nostr's equivalent of a subreddit, is underutilised at the moment, but I use it regularly and I find it quite useful.
Would you consider adding this feature in the future?