What's the point of imperial inventory?

I keep building these imperial levels and delivering supply workers to build items that show in my inventory screen (rebel secrets! security codes!) but I can't figure out why I would want to do that.

What do the imperial items do for me other than pile up in my inventory menu item?

Solution 1:

These items are used to complete Imperial Assignments.

You can tap on the floor below your Arrivals floor (It is not named in the game, but some tips early-on explain its use) to see - and complete - the current assignment. These assignments require an increasing amount and variety of Imperial Items.