Yes, there is. Variant ratings are supposed to represent someone's skill in a certain variant. If 1/4+0 variant games can be rated, a player doesn't necessarily have to good at a variant to get a high rating, as long as they play it quickly.
Well, to be fair, you can already play hyperbullet in the variants, so the "players can get high ratings from just playing very quickly" ship has already sailed. Of course, ultra would be even worse from that perspective, but hyper's pretty bad already :)