Only if you already have BTC. And a transaction takes more than a "few minutes" to confirm anyway.
Speaking personally, I did not own any BTC, and I did not have an account with an exchange. If I want to buy a few BTC to use in a transaction with someone else, it takes over a week. A few days to confirm a bank account at an exchange, and then 3-4 more days for the ACH transfer to put funds into the exchange, before I can finally buy the BTC.
This is also far from decentralized. Everyone accepting BTC as a just-in-time proxy for other currency are extremely reliant on the exchange they use to do the immediate conversions (e.g. Coinbase). Since you already need to trust some centralized entity, Stellar ends up being a much better model for this sort of payment, because trust can be distributed better (with BTC, Coinbase goes down and you can't accept BTC until it comes back; with Stellar, you can continue to use the appropriate credits for as long as the issuer is still trusted by people), and because you don't need to do any just-in-time conversions, you can just accept USD credit and hold onto that and exchange it for "real" USD at your leisure.