From a marketing standpoint, more the merrier if it is no cost. I would list them at the end of the other mainstream options so you don't have to wade through all of them to get to where you want to be.

I do find occasional use for the phantom modes that redistribute the center to L/R speakers.

I wholeheartedly agree with other posters that bass management is where it's at. If it were a choice between b-m and extra modes, there would be no contest.

--Keith--