As far as I know, the reticence has something to do with indexing on Google. When you change the title, the link to the article doesn’t change to match. This may impact whether search engines pick it up? Maybe someone more tech savvy can explain it better!
I’ve not heard of anyone being penalized by Medium for making such changes though. (Again, if anyone begs to differ, please let us know).
Bullet points are merely points, like full stops, but bigger. I noticed medium use them often in their articles informing us of new information. They are literally used to make a point! (You know what I mean now and are sighing, I’m sure!) Here’s one • I figured the way they present information must be how they want us to present our own ideas. (Perhaps!)