Which is just the PR message if you squash. To be clear, I'm not advocating for bad messages, but I am saying I don't worry about each commit and focus instead on the quality and presentation of the PR.
Definitely, but if you've made your PR with several different commits the message will contain all of the information for the whole PR, instead of just the message that pertains to the changes in that commit. It's not a HUGE deal, but it can make it harder to understand what the commit message is saying.