Can someone please explain the Walmart+ "shipping" option where they turn it into a delivery after the fact?

I ordered something from walmart as SHIPPING and walmart turned it into delivery and had a driver bring it to me. Which then made me upset because I had no option to tip and if I actually want delivery I make sure I tip. I wasnt home when it showed up to juat give cash after the fact. How does paying the driver work when walmart turns shipping into delivery? Do they pay you more or does it just look like a delivery order that no one tipped for?

Thanks.