EDIT: Let’s cool it with the downvotes, dudes. We’re not out to cut funding to your black hole detection chamber or revoke the degrees of chiropractors just because a couple of us don’t believe in it, okay? Chill out, participate with the prompt and continue with having a nice day. I’m sure almost everybody has something to add.
Modifying the theory of gravity to fit the data might be useful even if it’s just for modelling purposes. But it doesn’t make a theory for sure.
I am also an (non retired) engineer, but alas I have no theory of my own :)))
Oh it’s definitely useful, that’s what MOND theories are. If we didn’t do it, we wouldn’t now why it’s less likely than dark matter.