Trading is a losing game. You sell because you need liquidity to by things you need. You sell because you wish to re-balance your portfolio. You don't sell "to rebuy lower".
Trading is a sero-sum game, i.e. it is a losing game for the less smart half of players and winning game for a more smart half of players. So the answer seems to be an easy one:
if you're smarter than average, do trade, if not - don't.But:1. If you are asking if you should trade, you belong to the less smart/knowledgeagle half. So it's kind of catch-22: answer "yes, do trade" should be given only to those who don't ask the question.
2. Most of people consider themselves to be smarter than average. Trading would be very costly method of self-deception.
3. Winners to losers ratio in trading is probably 1:10 rather than 1:1. So even if you are really smarter than 8 out of 10 bitcoin traders, you still may belong to the loser's camp.