VXX/UVXY are so low here I expect to double my money on them once VIX spikes > 20. The VIX always spikes intermittently, look at 1year chart.
I successfully daytraded VXX back on flash crash day many years ago. These are tricky to trade. I buy the dip sell the rip. When they selloff I buy early reversals. When they spike way up I sell, like TVIX at 940. Multiple entries and trailing stops are key.
This is a rare exception to my rule of never adding on the way down, within reason. Eg I was long a few hundred shares from slightly higher, I bought 400 more eod today. Because VIX and etns like UVXY VXX are pivoting instruments, it's not if but when. My traders were skeptical when I said TVIX under 80 was cheap... til I sold weeks later at 940. UVXY under 6, VXX under 10 is a bargain imho (not a trading recommendation.... they could still drop much further).
Contango erodes value over time, like premium decay, so short swing trading holds < 3 weeks are best.