The strategy of OP is not easy to pull off because the price of bitcoin doesn't easily recover by $500 or crash by $500 every day. Imo it could work but not all the time.
That is why you should do the daily trading and be active, I believe if you have that huge bankroll it is still possible for you to make that happens because their volume on 24 hours is really much far than you can imagine. You can see big exchanges that having like billions of dollars traded on each coin, conpare to your $500 profit is really easy to do. You just need to be active on trading and thats all, no need anything more
The reason why I like to do day trading as oppose to just holding my coins is because of this reason. There is a possibility of being able to profit even if I had lost in my previous trade and the market is bearish. The small price swings are opportunities to make small profit. My intention is to earn small profit because once accumulated it would become bigger and every time I trade, I learn so it would be a great help to my next trades. I will be versatile then because I can profit in whatever market condition.