"Waiting on" and "waiting for" [duplicate]

While purchasing in Walmart, after sliding my card the card machine was saying "Waiting on cashier".

What does "waiting on" mean in this case and how it differs from "waiting for"? Would that be wrong to say "waiting for cashier" ?

"Wait on" for "wait for" is regional AmE.

It's a southernism extended into African American speech that has, in the last few years, become trendy. The exception is another regionalism, New York City, where people "wait on" line rather than "wait in" line.

It would be completely correct (more correct, if you ask me) to say "waiting for cashier." Only waiters (at restaurants etc) "wait on." Waiters of the kind who experience delays do not.