You can implement it yourself and host your own Bolt Card that will work with merchants worldwide.

There are an increasing number of merchants who accept it in the UK (where it started) and further afield.

It's easy for merchants to accept on Android mobile with Breez POS.

For self sovereign merchants, there is BtcPayServer with the POS app & NFC plugin. This also works nicely on Android mobile without even having to install an app, just a shortcut. It then opens full screen (as a Chrome PWA).

Or if they want to flip direct to fiat (for simpler accounting or to mitigate volatility worries), in some countries they can use the CoinCorner POS app (with KYC).

In the UK, there are organised and motivated individuals who help businesses to onboard and this is proving to be very effective.