I fixed a spelling mistake: https://github.com/flarum/flarum/pull/81
Spelling mistakes should be fixed.
A PR is click-click-done, whereas a textual description of the mistake requires small but real effort on the part of a project member.
And absolutely no one gives a flying crap about visibility in the changelog.
It's also been a trend in the past few years for people to make this kind of PR, which is very low hanging fruit, just to increase the number of projects they "contributed to" and their profile activity. The author may have not had this intention, but it sure plays into the stereotype.
Personally, I have sent these kinds of PRs out and received only approvals and thanks from maintainers. When in an approver/maintainer role myself, these kinds of PRs are trivial to approve and I appreciate them. The PRs that change a bunch of stuff, are large, hard to review, poorly described, poorly justified, poorly tested, etc., are the annoying ones.