[pizza234]

> other than using them in array literals

Well, array literals are very convenient in some areas.

Matrix types can be cleaned up across projects, one widespread area being 3d graphics. Previously, you either had to create a separate type for each matrix size, or use a backing vector (of vectors); the first solution is ugly (because of redundancy), the second is potentially underperformant (in cases where one wants to avoid dynamic allocations as much as possible).