I’ve always found the “convention over configuration” thing a bit of an odd descriptor for Ember. Outside of Ember CLI generating things for you or errors/unexpected results being thrown after something has been made, if you look for any documentation on those “conventions”, it’s really difficult to find (if it exists).
Do I really have to do things the “non-Ember” way just to figure out what the Ember way is on my own?
I found Ember to be very frustrating in that regard.
Ember is focused pretty heavily on convention over configuration which, IMO, ends up making everything a little harder to get into. You have to do things the "ember way" or you face a large uphill climb.
Ember is all encompassing as well. You make an Ember app. You don't make an app that happens to have some ember capabilities.
The reason react is popular (IMO) is because it's just the view layer. It allows for you to work with whatever other ecosystem you like in a fairly flexible manner.