Local conditions
Glare off water is a different problem
The Light Here Comes Up As Well As Down
Anywhere with water in front of it gets light twice — once from the sky and once off the surface. That reflected light comes in low and from underneath, which is the one angle an eave cannot help with, and it is why so many Gold Coast apartments feel glary at times of day when the sun is nowhere near the window.
A sheer is the right answer to that because it diffuses rather than blocks: you keep the outlook and lose the hard edge. Pair it with glazing that is doing its share and a west-facing living room becomes usable without going dark.
The second thing is the breeze. A sheer in a room that opens onto a deck will move all summer, and a curtain that moves needs enough weight in the hem and enough clearance at the floor to do it without catching. It is a small detail that decides whether you like them in February.