Casements, in most cases, do not utilize a pocket sill.

Sliders, almost universally, will have weep holes.

Sliders sit in a channel, so they have to drain via weep holes. There is no way around this.

Casements typically come boxed so they don't have normal sills, i.e. slopped or pocket. Although you could call them sloped if you got right down to it.