That’s not true at all, Kai has said before that one of the main priorities is to ensure backwards compatibility. In theory, anything you can do in OH1 can be done in OH2 (minus any bugs/quirks).
The main end user benefit, at least in my experience (and this is my #1 reason for moving to OH2), is a much streamlined set up for devices that are able to be auto-discovered/configured. You also have the ability to add/remove bindings/extensions/services from the UI, and a UI that is more modern and up-to-date (as I think the OH1 UI/Classic UI is ugly).
There are other benefits too but these I would class as “nice to have” such as the dependency management from Karaf so that when you install a binding/extension/service it automatically installs the other bits that it needs to work.
However if you’re risk averse, or not usually an early adopter, I’d say go with the saying “if it ain’t broke, don’t fix it” and stick with OH1 for the time being.