I think the concern is that the app seems to be a stop-gap to address some complaints and could easily become an app that is not supported or updated by ring which would mean back to Sq1.
Given the cost of these doorbells and for some, the annual running costs, the service from Ring is terrible.
I’ve had support calls with them and then forgotten about once they have decided the scripted responses no longer apply.
I was on the trigger to get a Nest over the weekend especially as I am “googled” at home but the one thing Ring has is compatibility with 8v doorbell chime boxes in the UK. Something Nest will never work with the current products and resolve it meant almost the same cost as the bell going to an Nest approved sparky.