I don't think his argument was that it's not possible to purchase items with crypto. To me, it sounds like he was beating around the bush and trying to avoid saying the use of crypto is more akin to bearer bonds or barter like trading.
He's also very right. If the asset does not have the capacity to do anything other than move between wallets, then it has no value. Those individuals taking long positions need to understand that they're not just buying digital currency, they are investing in a company developing applications.
Would anyone have invested in Windows if it didn't have an interest in continuing to develop new products for sale so as to grow as a company?
As far as I'm concerned - crypto is neither currency or asset. It's a ethereal representation of the financial support I, as an individual investor, am showing to a specific platform, company, project, blockchain, group, programmer... the list goes on.