ListenBrainz dev here. We wanted stuff like the ability to do stuff like "DELETE FROM measurement where field = blah" and that support didn't exist last time we looked. [0]
Another thing that's not mentioned in the post but was a pain point for us was that it's not easy to query for fields with "null" values [1].
I figure a lot of our pain might be because we're not as good at Influx as we are at PostgreSQL. We've been running MusicBrainz[2] for ~18 years on PostgreSQL, that knowledge will hopefully transfer over a little with Timescale.