This is taking my words a bit far.

Typing annotations are tedious and have to be done every time you want to provide typing information. It's easy to just not write them. I'd be surprised if anyone here *always* annotates every function they write.

Learning a bit of new syntax is something you do once or twice. Plus it's hard to avoid learning it, especially if you come across the syntax in someone else's code. And once you know about it, it's the natural lazy option over `if foo is None: foo = {}`.