Data point: I just ordered 2 x $1000 and 1 x $250 in a single order.

Within five minutes the first $1000 egift card showed up. Ten minutes later the second $1000 egift card was issued. About 30 minutes after ordering the receipt for the order was received.

An hour on, the $250 card is missing.

The whole process feels haphazard and reading OMAAT some are reporting receiving nothing days later and it being difficult to use the helpline. So, buyer beware as the IT implementation here with both Marriott and the third party does not feel particularly robust - shocker!