Well we are on HACKER news ;-) To mess around and learn something would be one reason. Maybe you already have the hardware. Why selfhost anything if cloud does the thing?
An other reason would be because your company does not allow any source code leaks and thus every developer either has local models or none.
6 T/second local model while your colleagues have 200 EUR/month claude does not make much sense. At least I can't see a use case.