Have to say I quite like the Ringo app

I recall the 'brefore' times when you'd have to ensure you've got sufficient loose change to put in the machine (and always worry that it wouldn't give you a ticket anyway). You'd park, trundle off to find the machine, trundle back to the car to fix the ticket, etc. With the app there is none of that: park, go. If you let it, the app will even tell you where you are so you don't have to dick around with 4-digit parking IDs.
I was initially wary about putting an app on my phone, with visions of needing a different app for each car park. Resisted for a long while, but one day I had to park up at the local hospital and there was no getting away from it - either phone up some number (not an option for me) or use the app.
A straight-up benefit is you don't have to put in 3 hours worth of coins because hospital appointments are never on time or last 10 minutes. Just go for the minimum and if it runs out just extend it some more without even getting off your seat.
Another time I had to visit some shop in London and, via Google maps, found a car park a street away. Rolled up there on spec and the same app I use here paid for the parking there too. Just makes life a bit easier.
Mind, when it's not in active use it is killed off, and made to stay off, by Greenify.