You won't make a fool of yourself either way, attachments are optional. Attaching a file to a devlog just marks it as the file that post is about, so readers can see which build the patch notes go with. It doesn't create a download link, which is why your buyer couldn't click it. An itch admin explained it in an older thread: they keep downloads on the project's download page on purpose, so different versions don't end up floating around on different posts (/t/182672/cant-get-devlog-attachments-to-work).
So for a patch notes post, attaching just the file that changed in that patch is a sensible habit, and for a general dev update you can leave it empty. If a buyer can't find the update, pointing them to their download page or purchase email like itchboy said is the real fix. Congrats on getting v1.1 out.