I have a few thoughts
-Your potentially harming other peoples videos if you are just staying long enough to write a comment and not watch their video - not saying thats the case. This gives them low watch time % which they won't thank you for.
-I keep hearing this (i think) nonsense about how to "gain views from other videos".. This assumption presumes that all you have to do is leave a comment and that someone will see what you write and then press on your channel logo. I can't remember ever visiting someone's channel because I thought their comment was so enlightening i would never know the meaning of true happiness until I go visit their channel.
-i deletes comment and block people when I can see it's obvious they had no interest in my content and are just trying to promote themselves.
-sometimes I leave comment on another creators video to try and support them.. its shows google they have engagement. But I watch the whole video and leave a comment that's valuable some how.