This post doesn’t answer my question. But is helpful to understand their statement about destroy fiat, let’s see if they preserve that.

Sorry I haven't used that feature and can't comment. But maybe this blog post answers your question https://www.bullbitcoin.com/blog/send-bank-transfers-using-bitcoin

runningbitcoin

It could be interesting when they expand for other territories, because of "spend bitcoin" method. But I would like to know what they do with the bitcoin that they buy from us to pay our bills.