In my opinion, you are taking a HUGE and unjustified risk by submitting a GRE score as opposed to a GMAT. You bring up some good points, but what it ultimately boils down to is that the GMAT is for your MBA. If you submit a GRE, adcoms will wonder why you were taking that test in the first place. It will show that you don't have direction towards an MBA, and could directly hurt your candidacy. Without comparison to your fellow applicants, it would be extremely challenging to get into top schools. Only top candidates who are strong in other areas will have a good shot. Not to mention, if you do badly on the GMAT, you chances of doing significantly better on the GRE are most likely extremely low.
Adcoms are trying to bolster applications, but this might be a backdoor way for someone who wasn't considering an MBA to maybe try their hand at it. I don't feel that it should be the other way around. If you want to get an MBA, the GMAT is the gold standard. Any time you spend studying for another test will be time away from getting the GMAT score you need.
But hey, if I was a prep company, I would sign you up for GMAT and GRE prep. Hey, and if you have a good verbal score, maybe the LSAT is for you. Well maybe you should try all three and see what you like best.
Seriously though, spend 100% of your time on the GMAT if an MBA is what you want. Get that 700+, and go to your top pick because a 1550 GRE might just make those Adcoms wonder, "Does this guy really want an MBA?".