Why do some contactless payment terminals require the launch of Google Pay?

Question

G Pay

I noticed that occasionally there are terminals that require the launch of the GPay application to make a payment.
The usual payment scenario: unlocked the phone, brought it to the receiver, the payment went through.
The phone does not respond to terminals that do not work this way. No error, no vibro. Zero reaction until you launch the application.
Guaranteed to behave this way all vending machines for electric trains in Moscow. Today I encountered the same behavior of the POS terminal of Tinkoff Bank.
Similar behavior is observed on two different smartphones, i.e. The devices are clearly irrelevant.
What security standards or protocols govern this? Who is to blame - a smartphone or a terminal? Why is this happening?

Answer 1

They do not and cannot demand.
You cannot launch Google Pay on a card, but these terminals somehow accept a card ...

Answer 2

there are no smart
miracles - the app (GPay) listens to nfc in the background, you or another one interrupts (it’s strange here, because usually it’s the same banking one, it should pop up) or smart stupid - it extinguishes such a rumor in terms of nutrition