This is a bit misleading - PayPal's 21-day hold only applies if you received the funds as payment for goods and services. Even in that case, the funds can be expedited to release in 3-5 days once the buyer marks the item as received. It's more for buyer protection than anything.

If you're in the US and receive money via a "Friends and Family" transfer, it's just as 'instant' as Venmo.