Not strictly necessary, no. But the example I wrote was getting at was meant to point out that this bifurcation can make it harder to compose generic types. It'

Not strictly necessary, no. But the example I wrote was getting at was meant to point out that this bifurcation can make it harder to compose generic types. It's not really an ideal design decision for modern C# so much as a hold-over from the language's early years, when idiomatic usage favored a much more imperative style of programming.