The separation between the view and logic is great. So you can also run Blender command line only and everything is still working. Trow a script at it and you can do whatever you like.
This video is another great example of it's power.
But it was functional, and had some really great ideas, and it was free (which I needed on my nonexistent allowance)! I just assumed that the real cost was just a brutal learning curve. Then the really cool open source movement started for it when NaN went under, and people spent the next decade working to make it better.
It's always been a program for enthusiasts and passionate people, and it really shows. After half a decade I went back to it and was dismayed to realize I had no idea how to use it any more. And then 15 minutes later I was right at home. The learning curve's still there, but there are guideposts everywhere in the application, and the documentation exists! That you can throw Hy on top of it and live code it is just one more spiffy example of it working as intended. I would go so far to say that it's a core idea, since the blending engine made so many cool things easy (and possible) way back when it had an inscrutable interface.
TL;DR: I agree wholeheartedly.
This is such a great thing, I wish more apps would adopt it -- it's such a joy to use I keep looking for excuses to use it when I don't even have a need to...
And what's more, the tooltips aren't just examples, they dynamically update to be /exactly/ what you'd type into the console or a script to get that effect. Eg when you have multiple scenes, the docs for how to change scene settings will reference the actual scene you're looking at: http://shishnet.org/ufufuf/blender-tips.png
Not just modelling, but compositing, animation, video editing...