I find D easier to use than Rust or Go because of familiarity. It is very obviously C and C++ inspired but without all the sharp edges.
I also love D's metaprogramming. It feels almost like lisp. Go's lack of generics doesn't allow this and Rust's macros don't feel as comfortable for me.
Yes, D is smaller but it's also big enough for me. I don't feel like I'm missing out on much when I'm using D. If I need a library to do something that isn't already in the fairly generous stdlib, I can find it on DUB.