Just like anyone can take anyone's credit card and go shopping - but in contrast Phones are (or at least can be) much more secure.
The credit card doesn't work as age verification.
I think they "fixed" it. I think it has some effect now that only works if you tilt the phone.
To be honest I just overhead the bouncer talking about them liking the app. Maybe I misheard it.
Maybe bundling these under the same system is a mistake and they should be separate systems with different considerations; it would certainly help with arguments about it online ;P