I found this issue
where it's stated that this PR allows people to select in the settings that default title for the PR is taken from branch, what is the default of what GH does in the web UI.

I can't see it any more and the PR title is set to the commit message.
It is a best practice to include the ticket number in the branch name, and various automations are based on having the ticket number in the PR name, so setting the PR title to the branch name seems reasonable.