Eh, "no fees" is pretty meaningless when you look at the broader flow of assets outside of this single transaction.
To acquire crypto in the first place, I likely pay fees or have purchased mining equipment.
Crypto assets are also volatile, so I'm possibly losing future gains, realizing losses, or paying interest to borrow against my wallet.
Also, one of your premises is wrong -- that this isn't possible with fiat. I myself pay many people instantly to their bank account using Zelle with 0% fees.
As a merchant it isn't easily possible in the US and Australia (as far as I know) to receive money from customers with no fees in an easy, automated, online way.
To acquire crypto in the first place, I likely pay fees or have purchased mining equipment.
Crypto assets are also volatile, so I'm possibly losing future gains, realizing losses, or paying interest to borrow against my wallet.
Also, one of your premises is wrong -- that this isn't possible with fiat. I myself pay many people instantly to their bank account using Zelle with 0% fees.