all they have is a thin coverage with incorrectly aimed hairs.
MAybe, but thin coverage is always better than no coverage. Amnd don't forget that you can transform that "thin coverage" in a completely ok coverage with just some sprinkles of concealer, if you really want. Which is not available if you have no coverage at all.
Incorrectly aimed hairs is not an issue, if the hair transplant is done by a good surgeon.
And in a lot of cases, the reamaining hair of balding people looks horrible/sketchy.