That's a good point, however, the important aspect of typeclasses is that they're type-checked, not that they're compiled via monomorphization. Also, I believe

That's a good point, however, the important aspect of typeclasses is that they're type-checked, not that they're compiled via monomorphization. Also, I believe that the way that typeclasses are compiled is at the discretion of the compiler, so actually typeclasses may be compiled in the same way as C++ templates. Another point is that monomorphisation isn't always possible, because a function could be run with an infinite number of types.