I haven’t seen a clear use case for why somebody would want to conduct a transaction using bitcoin (vs regular money) other than doing something illegal or avoiding taxes (which includes hiding your identity when converting to/from fiat currency or just buying / selling all in bitcoin and never convert it). Everything you can otherwise do with Bitcoin you can do with the regular money system but better (eg goto your credit card company and get your money back if you get screwed which has value even if you get a small discount using Bitcoin. Although PayPal and Venmo are free).

Other than transactions, there is just speculation which can create huge gains (and losses) due to high volatility. But that is increasingly sounding like a pyramid scheme. Unless the illegal activity is able to grow. Or the world collapses.