I agree it's something that needs to be dealt with, but an you name a plausible scenario in which this would actually happen and in which the desired behavior would be that you get silently some garbage filename written to your disk?

Let's say you get an EILSEQ on accessing the dirent with readdir and now have to debug how you got some corrupted filename you clearly didn't want in the first place, remount and fix it. How is that worse than having the corrupted filename and not knowing about it before something more insidious happens?