It just popped up in my mind.
- You could decorate any room as you like. You don’t even need to step out of it most of the times.
- Other people can be projected inside it like Voyager’s doctor.
- Also rooms could be much smaller. They only need to be big enough a human(oid) can fit inside.
- In emergency cases most holograms can be shut off to match increased energy demands by weapons and shields. You only really need seating/bed and a (non-exploding) console screen.
- Much of the specialized rooms like a bar, med bay, etc. won’t be needed anymore as a holodeck can imitate all of them.
It irritated me a bit that a Discovery gets fancy floating warp nacelles but holodecks are… wait, does Discovery has a holodeck? I don’t remember seeing one.
Expensive?
According to Picard in the Movie First Contact money doesn’t exist anymore. I guess those latinum bars are only used by Ferengies, in border systems and outside the Federation.
That doesn’t mean there’s nothing that measures expense. The Federation might have a lot of available resources but they can’t be infinite.
They have replication technology, so their resources are infinite, provided they have enough energy.