Strictly speaking very little is needed. You can write everything in assembly if you'd like. Helpful, though? There's absolutely no question. Type classes like

Strictly speaking very little is needed. You can write everything in assembly if you'd like. Helpful, though? There's absolutely no question. Type classes like those you mentioned make programs more concise, more understandable* , and more general. All of those are good things. * Specifically, understandable to people who know the language and concepts. Trying to be understandable to everyone is a terrible idea. For example, Cucumber.