What's the risk of buying low and selling high with low interval like 500 difference?

This might be so dumb but I had an extra $6k and I just bought bitcoin at 58,000 and then sold at 58,500 and made a few bucks. I started doing that again and again even with like 200, 300 difference and I made $200 in a span of 5 days. And I'm feeling like this is too easy. What am I missing here? I am not day trading or anything. Just an easy buy and sell. Forgive my dumbness.