Why do ATMs (Cash Machines) display a thank you message for so long?

When I use an ATM, as soon as I have my card and cash I’m walking away. I don’t hang around to read any “thank you” screen after the transaction is complete.

When using an ATM immediately after someone else in the queue, I’m often frustrated by having to wait for up to 10 seconds while the machine continues to display such a “thank you” screen, during which time I can’t insert my card to start a new transaction and the user the sceen is intended for is already halfway down the street.

Does anyone (industry insiders?) know a good reason for this?
If it’s just a way of thanking the previous customer, why can’t I insert my card until it has finished displaying?
Is it actually just something to look at whilst the machine is busy doing something, like a splash screen?

Surely the banks/manufacturers have figured out that it will rarely be seen by the intended user, because as far as they’re concerned the transaction is complete as soon as they have their cash/receipt/card etc.

I only have experience of UK cash machines, other countries may be different.