It can be worthwhile to bless a set of libraries. Even if it seems like it can be done unofficially, it helps to have it done "officially", at least, from the point of view of a newcomer to the language. Haskell's getting some mileage out of that sort of thing, lately, starting with the "Haskell Platform" and lately moving into Stack, a blessed set of packages that are maintained in certain snapshot sets and guaranteed to compile together.