It's not about the bets. If BTC can transparently be converted to USD or GBP then it does actually offer value to the person using BTC to buy services. I'm not sure why you're so adamant about insisting that Expedia isn't buying into "bets" or whatever. Having parts of a transaction happen off-chain doesn't constitute a repudiation of cryptocurrency. Not everyone is a Bitcoin maximalist. Demonstrating it has value for people is enough to support the GP's comment, in this case value for people that hold BTC to purchase real goods and services, the same way any other fiat currency is used. It's not like a non-US entity that takes USD as payment is endorsing US political actions, it's just trying to receive payment for goods and services.
I'm tired of these shifting goalposts in crypto conversations. They always go like this:
1. I derive value from crypto
2. There's no value in crypto! Show me a usecase!
3. <Presents usecase where crypto is used to derive value>
4. But that uses Fiat/off-chain/<something not crypto>/<vendor that doesn't know what crypto is>/<workflow that's replacable by fiat> so crypto has no value!
The claim the GP made is that an individual can derive value from crypto, not that this value is untainted by fiat, off-chain movement, or any of the other incidental claims. When you use USD or GBP to buy a good, the good itself has probably traded hands between many currencies before the final product was sold to you using the fiat you paid. Does that mean USD or GBP are "useless" because input costs for your product were paid for in RMB? No, you still derive value from fiat.