Could be?  Your measurement of odds seem in the ballpark of reasonable, even though I continue to be inclined towards 50/50 thinking because I hate to make any bets in the way that I approach my BTC holdings (which I prefer to assure that I am adding to my reserves, rather than gambling that I may or may not add to my reserves).

Anyhow, I merely buy if the BTC price goes down and sell if the price goes up.  Seems safe, no?

In this case, I have already sold all the way up to $9k, so in recent times I have been put into buying mode, so my buy orders have been executing as the BTC price has been going down.  

Seems to work a lot better than trying to guess, and even if I were to have more confidence - such as something above 60%, which you seem to have, and even if you are guessing in a kind of reasonable way, to me, it seems as if you are betting too... because one thing is to close a long by selling a little bit of BTC, but another extra risk is to add leverage onto the situation by entering into a short position (which is what you said that you are doing)... too scary for me, and too much gambling for my risk tolerance temperament in terms of my preference to preserve what BTCs I have worked so hard to accumulate over the past 5.5 years.