If you can buy anything in the physical world with your bitcoin/crypto, that's excellent.
For example, I always top my phone bill with BTC. It is a 3rd party service offered by Bitrefill.
It is more simpler for me than having to buy scratch cards with the local currency and redeeming them.
If only you could. Unfortunately, the number of merchants/businesses accepting Bitcoin are limited. Adoption is growing, albeit at a slow and steady pace. We still need to depend on Fiat to "live". It's technically impossible to survive entirely off crypto (in this case, Bitcoin). Many people say Bitcoin is "risky" because of the unstable (volatile) market prices.
While Fiat often has steady inflation rates (like 2%, for instance), Bitcoin's price can dip way above 20% in a matter of weeks or months. At the same time, it can increase exponentially, giving you two to three times more returns. I hope that as developers increase BTC's transaction capacity, more users will get on-board. Increased institutional capital inflows might even help make BTC less volatile. We'll never know what the future holds. So better be prepared, just in case.
You make a great point about merchant adoption, but the crypto circular economy is growing faster than people realize through services like Bitrefill. While a local grocery store might not accept bitcoin directly yet, being able to instantly buy gift cards for supermarkets, gas stations, and flights means you can actually live off crypto much easier today than a few years ago. It’s an intermediate step, but it bridges the gap while we wait for native adoption.