This is one of those ideas that is so simple and elegant that it makes you think “why did I never think of doing this?!”
Neat trick! I don’t think I’ll namespace everything this way, because there’s some aliases and commands I run so often that the comma would get annoying, but for other less frequently used helper scripts then this will be perfect!
Maybe then try ending your commands with a comma so that you don’t break first-char autocomplete !
I do something similar with build trees, naming them +build, +cross-arm etc.
This convention was suggested by the GNU Arch version control system years ago (maybe 20??), but it's really useful for the same tab completion reason and I have kept it for almost two decades, even when I switched to git.