So another aspect of making the ship design more modular and designing ship hulls which you can later add components on (a bit like you can fit different missiles in the same launcher) is that it could allow you to also temporarily refit the ship for a specific mision profile.
Say you have a big carrier with a huge hangar space. You need a ship with a huge sensor array to go check something stat, you don't have time, or maybe resources to build a new ship, but you just so happen to have a very large sensor laying around. So you stuff it in the hangar space, maybe with some extra generators and hook it all up. Presto! You got yourself a temporary listening ship. It far less efficient as purpose built ship in terms of sensor strengt to hull strengt as you are kinda have to make it fit into a space it was not made for. But hey, you got something that works in a pinch.
This would allow for more tactical options, interesting retrofitted pirate ship or other people and organisations engaging using haphazard ships as need be. Or just spyops where you can disguise your ships, like stuffing a hangar in a transporter or whatever to surprise your enemies.