[jcelerier]

> Once they're safely out of Boost and implemented by the stdlib they're an order of magnitude more convenient to use.

I don't understand this. Most of the time the API doesn't even change; you can just do `namespace lib = std` or `namespace lib = boost` according to which one you want to use. In my own code for instance I have a header where I choose the std::, std::experimental or boost:: version of `optional`, `string_view`, and `any` according to the recentness of the stdlib I'm using; nothing else is needed.