Define 'interact.' If by that you mean shoot, then I don't really see the use in that either. Sure, conceptually being able to nuke/bombard/glass a planet from orbit sounds really cool, but in a voxel game, in practice it just means that anything you build on a non-homebased planet can and will be destroyed by someone with a big enough doombrick/ship. Besides... wouldn't it be a lot more interesting to have to actually stage a planetary invasion, with fighters, bombers, troop transports and the like, than just wipe everything out from orbit with one rather unspectacular shot?