Online banking wire transfers are subject to a relatively low daily limit. You must appear in person and show ID to wire large amounts of money.

The victim may also have a chance to cancel the transfer, because they’re not instant. (especially outside of business hours)

It’s just not an attractive way to mug someone, it’s easier to take them to an ATM.

This is only true in the crappy system of the US.

In Europe a wire is instant with no recourse.

Most banks have processes for giving money back in some of these cases.