I would not recommend using “complex as simple” as a final solution. Unless things have changed since UE3 it’s there for very specific cases and to make your life easier during initial block out so you don’t have to worry about collision when you’re just testing levels and pieces of geometry, and collision can be very performance heavy (although it may ultimately depends on your game).
Generally the workflow with static meshes is to create a few levels within an architectural style and then break those levels down into reusable pieces. E.g. you might have a 200x200 unit floor piece that can be used dozens of times and hopefully in many different ways, and a 20x200 trim piece that can add a little more detail to it or cover seams.
And typically creating collisions should be relatively quick, you want to use as few shapes as possible and keep them as simple as possible.