2 years ago is decades in the front-end world. If we make decisions today based on the state of things years ago, we'd be screwed.
And if we CAN'T "make decisions today based on the state of things years ago", then we're really screwed.
But Ember has likely come a long way in that time - I think this is mcardleliam's point.
Also you're flat out wrong: Ember-cli isn't really anything to do with the framework. You don't need it to write Ember apps, it's just the communities command line tool for managing Ember projects. That's all.
Practically, there are Ember modules/extensions/features that require Ember-CLI to work or are a huge pain to work with, if you don't use the CLI...
for example animation libraries or glimmer.