Let's say someone has a Strike account. They move USD from their bank account to their Strike account. They DON'T buy any Bitcoin through Strike, maybe because they don't care about owning Bitcoin, but they pay the company/person (who prefers payment in Bitcoin) for a good/service directly. And maybe they're getting a large discount for paying in Bitcoin.
Would this be considered a taxable event? I would think not because Strike is the one doing the conversion on the fly - the person is just paying someone else with "cash" for a good/service.