It's been almost a decade, a lot of bugs, annoyances and slowness has been ironed out. Most important libraries are py3, which is a biggie, and py3 changes were backported via __future__ to py2 so you can easily begin getting used to the syntax in current apps.

So now that you are used to using print("hello") instead of print "hello" and not having to use u'whatever' all over the place - it was a perfect time to experiment with toy apps in python 3, since they are mostly backward compatible with python 2 without all the 2to3 nonsense. Even ubuntu made it default.

Which leads us to asyncio, the killer feature - people were prepped to move...but didn't have a really compelling reason to...until now.