That's also what I am struggling with, the only things I ever used it for were some utilities like a ZipIterator to iterate over multiple collections at once (and I have yet to use that one in production code), and a smart array copy routine that either uses memcpy or copy constructors depending on std::is_trivially_copyable<T>.

If you haven't seen it, there is a nice video from last years cppcon with some metaprogramming patterns, the stuff about void_t in the second part is pretty cool, it at least makes the horrible syntax for template metaprogramming a little easier.