vol surface, if you understand how to trade these. You can short long whatever appropriate without hastle. More money with leverage on futures. Trade pretty much 23×5.5. You can control what you want to hold.
To also give UVXY some credit, advantage might be (compared to above points) that if you want a rolling, month ahead exposure you can do without adjusting (because UVXY does that for you) and sizing is easier (as UVXY options are generally smaller).
True, but again to give UVXY some credit, those options can also be traded in extended hours (albeit only 0.15 x 5 extra compared to "normal" equity options).