I think that there's one important point to consider that may not be immediately obvious, when deciding about commit messages in FOSS project, even if you are not accepting contributions and just want to share your work for others - auditabilty.
7-zip has been receiving critique for this for a long time - not having commit messages makes it way harder to check what the actual changes were. Sure you can't trust commit messages during an audit, but it makes it a lot easier - either you immediately notice that they are lying, or they are correct and will help you with understanding the change, so you can decide for yourself whether it's safe.
Of course, the author is doing a lot of work for free, that he offers to others, so we have no right to blame him for it or demand he changes his approach. I'm grateful for any FOSS project, and demanding from someone directly that he's doing it wrong and should do it some other way (or belittling him for it) isn't OK. However, I'd probably be very careful when encountering a repository like this, and reconsider whether it's worth adopting. Which is absolutely ok and I don't blame the author for it in the slightest - it's his repo and his work - but I also think that auditability may be something the author didn't realize, and assuming his goal was to share his code with others i.e to build a portfolio, may affect his overall adoption rate. But it's also ok if he simply doesn't care about that.
But in general, if you're making a FOSS project, I'd recommend sticking with good commit messages.