It's probably in double format because that's the format all the calculations should need to be done in. It's possible it has to recast everything on the fly but I'm not sure on that.

I can't think of any reason they wouldn't give us an overloaded int function, otherwise, since all scene coordinates are effectively integers, anyway.

I guess it's a precision over memory usage balance since they don't figure anyone will actually put 100's of thousands of polygons in a scene.

I only put about 9000 in my largest one...