I believe Colt used the rowel hammer on the Commander for three reasons:
1) It is one way to eliminate "hammer bite"
2) It is practical in that it reduces the tendency for a cover garment to get trapped and torn between the tang of the grip safety and the hammer. In my experience, this is a real issue with a stock 1911.
3) It looks cool.
I do not believe lock time had anything to do with the original choice by Colt since the National Match was offered with the spur hammer at the same time the Commander came with the rowel hammer. The skeletonized hammer was the result of the crucible of competition and made popular because it looks good. I really like the functionality of the rowel hammer and have it on three of my 1911's. My cover garments are also much happier.
As for beavertail grip safeties, there are a few good reasons to use them.
1) The biggest advantage is one's hand is closer to the bore axis, reducing muzzle flip and perceived recoil.
2) A beavertail will also insure there is no hammer bite although this can be accomplished in other ways.
3) It looks cool.
As I continue to shoot 1911's, I have come to appreciate certain grip safeties a bit more than others. There are subtle differences that extended shooting tends to expose. The one that seems to best fit me is the S&A, and the one that fits the worst is Wilson's.