IMHO: We recently had the sharpest spike in volatility in history (change/time)! This change exceeded 80% change, resulting in XIV exceeding their termination clause. Just a bit more volatility could have hit the 100% change, which would cause SVXY to go negative! What is the likelihood of this occurring during the time you have long capital allocated?
I think one needs to consider the possibility of the "termination". Before this month, this possibility, did not seem likely!
Having said that, I am long SVXY, but am less optimistic about longevity of the instrument.
(The premiums of the options seems high to me, so I don't trade them.)