I typically highlight what I like: A phrase, a line, the flow of said lines, rhythm, tone, etc. That is how I use the highlighting feature. If I left comments on everything/every piece I highlighted, I’d get capped (meaning, Medium would suspend my account for a number of hours until I am able to respond/comment again). I try my best to avoid that now as I have been capped quite a bit.
I hope this explanation helps, Sam, but I will keep in mind to respond a bit more to your work with reasons for the highlights. Thank you, again.