There really is no reason to not have drone vessels...
I don't want MTU universe dominated by ships that have no place for PC's...
Well, that won't happen clearly...
Fighting ships need human crews for human decision-making...
Why? IFF and protocols should eliminate that before long. We already have hunter drones that could well be autonomous once loaded with a target profile.
At the very least manned space fighters are a non-starter. IF space fighters are valid combatants. If not then just make them bigger until they are, and call them corvettes, or destroyers, or whatever. You have more room for what counts in a fight; weapons, speed, armour, and speed.
...and also because some of them are likely to carry human crews for fighting in conditions where robots are unsuitable.
What possible conditions could exist that are unsuitable to robots but suitable for humans? It'd be easier to protect circuits from any environment than humans.
Further, human crews are generally required on passenger ships, not to mention those free traders and tramp ships which are effectively a home to the Traveller crews whose job is to provide those skills that really require a human touch.
Skills like what? Steward? MgT has "Luxuries" to replace that. Medic? Have you seen the bedside manner of PC medics?
I'd sooner trust an AutoDoc...
Homes for the crews? Sure. Tonight on "Multi Million Credit Homes of the Poor and Unknown"... without those jobs (replaced by automation) the "crews" would have perfectly fine jobs somewhere else and a home that doesn't require 10s of thousands of credits of upkeep a month to cover the mortgage, and skipping a little maintenance won't leave you stranded in space facing a slow death.
Incidentally, the idea of not equipping weapons platform drones with autonomous smart systems able to use their own initiative is even more important when it comes to the concept of designing a ship of any size, designed for combat, but automated. It's a matter of ethics - the drones might be doing killings, but there is still a human at some point, pulling the trigger.
Again though, why? Or more precisely, why do I need a crew of tens or hundreds to maintain the ship, man the turrets, fly the fighters, etc. etc. etc... when all I really need to satisfy even that requirement is a few officers?
Just playing Devil's advocate