My idea came from talking to a friend that is building a large ship.
Merging Constructs would be a nice option to use in building Modular / large ships,
Example 1: you're building a large ship and you need more room in one direction. you can take a second Core, and "Merge" it with the first Core. and extend the build area in 1 direction.
Example 2: you could build modules and connect them to existing ships. A Cargo ship can pick up a Client's cargo Module attach it to his / hers ship and deliver it to the planet for the client. this would open up endless possibilities in ship and habitat construction. Instead of deconstructing a whole ship just to add more living space for friends, you can simply add another module.