How to tag payment booth in gas station?

[dmfr]

How should I tag a payment booth in a gas station?

Please refer to this image for an example:

The single function of these two buildings is for a gas station employee to be inside, checking out gas station users. There is no convenience store nor any other products that can be purchased, only fuel payments.

I was initially leaning towards shop=convenience or shop=kiosk, but there is nothing people can buy there; only pay for fuel.

[InsertUser]

If it’s just part of the fuel amenity then I’d just extend the amenity=fuel polygon around them and tag them with the relevant building tags. Something like building=kiosk might work.