Yeah US banks generally can't (or won't) move money that quickly, so Paypal/Venmo/CashApp fill the niche. I've only seen the $25 fee when sending money from a US bank to a UK bank though-- I think it was because it required a wire transfer.
The claimed advantage of crypto is that there's no oversight or limits on the amount you can send, whereas banks report any transaction over $10k (or something like that) to the IRS.
I talked to someone who runs an investment fund about crypto and he said they bought some because maybe people will use it to buy "planes and stuff" one day. Seems dubious.