According to this question and its accepted answer: Would Star Trek holodecks physically affect you once you exit the Holodeck? it is possible to remove matter from holodeck and it will remain stable, when using a mobile emitter.
Could Starfleet create ships with a huge battery and a mobile emitter as a core and generate the ship around it?
- They would be more modular
- Ships would be cheaper (many ships contain a holodeck)
The crew would die instantly when the ship ran out of energy. But in a normal ship they wouldn't live very long without communication, fresh air and water.