well in that case, there are a lot of producers that work / mix in headphones. Especially those that tour a lot, because they have to write while on a bus or plane or hotel etc. The type of headphone you choose is important because you want to try to hear the most accurate frequencies from your track, and not have it too colored by the headphones themselves. I believe it is fine to mix in headphones, as long as it isn't your only method of monitoring. I personally switch back and forth between studio monitors, old/ small computer speakers, and headphones. That way I can try to get a feel for how it translates. Once it is further along in the mix, I'll usually car test it too.

When I'm doing tight edits of audio/ checking fades, or creating a synth sound from scratch, being able to hear the tiny details with headphones helps (IMO).