It is a small leap. The balance in your bank account is also a number without a physical presence. It has value because you can convert it to physical goods. The same is true of a Bitcoin balance.
Currency is a contract, it's inherently intangible.
Bitcoin is not a currency, and it's not used for anything, so it's a really just a number, that someone may speculatively want to pay money for, due to the fact a small number of other people will pay for it, but unless there's a more broad acceptance of it, the implied value will also fade.
If NFT's implied ownership of the Baseball card itself, I think this would be another thing altogether.
