New to Investing: Why Not Just Buy Low, Sell High Repeatedly?

Hey everyone, I’m super new to investing directly in stocks (have only done mutual funds so far), and I had a question that might sound naive. I was wondering—why don’t we just focus on 3-4 good small-cap stocks or crypto coins, and keep repeating a “buy low, sell high” strategy? Like, if we set up auto stop-loss and buy orders, wouldn’t that make it easier to grow money consistently over time? I understand there’s probably more to it (since it sounds *too simple*), but I’d love to hear from the more experienced investors here. What am I missing about this approach? Thanks in advance!