One caveat to GH Pages is if the repo’s public then all your amendments, typos, mistakes etc can be seen in a diff due to the way GitHub works. Not sure about private repos however. You may be able to conceal mistakes with that but not sure
I'd bet a significant amount of money that in most cases no one will ever bother to look through the commit history...
And if you're really worried about it you do your work in one repo and "publish" to another.
Or git commit --amend and force-push :-)
If you're publishing a site to the internet anyway, anyone could download every page on your site, submit it to archive.org, take a screenshot, or manually copy your posts onto a notepad. I find the GH Pages + Jekyll workflow works really well for my purposes, and it's been a nice way to play around with static site generation to boot.