Two things:

1. As Oz mentioned, bottoming is NOT submission. Many Dominants choose to bottom as a learning tool because they are able to experience a lot of the "training" aspects of submission-- play, positions, protocols, etc-- without actually "being submissive." They can feel what it is like to be spanked, to kneel, to use protocol... It really is a good training tool-- akin it to say, basic training of the military (VERY loose analogy!) It is VERY common to find this type of training in Old School lifestyle, and it has permeated general BDSM as well, to some degree.

2. Moved the thread to Dominant's Dungeon, as it seems to fit there better. Enjoy!