Yes. Margin-traders use their money too but they go leveraged 5-100x. Me, I have X amount of BTC on Binance (which is never sold into USD) and I borrow up to 2x my principle from them at any time. Hence, if I think I caught a good spot I'll buy BTC with their money. If BTC goes up the value of my principle increase and I buy more BTC with their money. Eventually we hit a top, I pay them back their fiat and keep the difference in BTC. Rinse and repeat.

It's very similar to what Saylor does but I've been doing this much longer and I do it on a smaller scale.