I think it's creating for the worst-case, but I'd have to RTFM.
I prefer this.
You may need to double-check the documentation, but the idea is that if I pre-allocate an array of the right type, I get the benefit that it will be a homogeneous array and I won't have to cast. I'm allergic to casting, even with run-time type checking.
An IDE is no substitute for an Intelligent Developer.