>Pay-on-exit car parks are the answer to this

Except having the actual barrier is expensive. The license plate reader is cheaper, so they'll do that instead, and if it malfunctions, hope you don't mind paying for a full day of parking!

Peek (parking) experience is the car having a tag and paying for itself, on parks, fuel pumps, toll roads at 120km/h (75mph), etc.

parking apps tend to replace metered street parking in my experience, not garages.

> Pay-on-exit car parks are the answer to this. Combined with contactless card payment and that's peak parking experience.

US here (you are presumably elsewhere given that you said "car park"), but I can't remember ever seeing a parking garage that had a parking app. All of them are like you describe, with pay-on-exit.

I mainly see parking apps for street parking (where pay-on-exit can't work), and sometimes more basic parking lots where there isn't room for the entry/exit gate and hardware, or lots where it's bare-bones enough that the owner certainly isn't going to spring for the expense of installing something like that.

In Austin, I've parked in a handful of parking garages that require using an app. They have license plate recognition on entry and exit, and they mail you a nastygram if you enter/exit without linking a credit card to your plate online.