This is very much how I see it too. For me a giant step in feeling fluent with the program was recognizing that I could use “actual” containers when they happened to be convenient, for instance to hold notes about an upcoming specific event or on one confined theme. But – the discovery – that I could create virtual containers whenever I wanted, as circumstances and needs changed. Moreover, I could create those virtual containers either through agents or with the (miracle tool) attribute browser.
So, yes, I’m happy to speak of containers – with the caveat that, at least for me, the constantly re-invented ones are the most useful.