OpenGL vs Direct3d/DirectGraphics

Wonder how wise moving libSDL DirectX layer to use DirectGraphics
instead of DirectDraw would be and what the implications are for
OpenGL. Implementing OpenGL in terms of DirectGraphics would be a
nice fallback if native OpenGL hardware drivers are unavaialable.

I have a question: if you use OpenGL hardware accel drivers (and
consequently cannot use DirectDraw), you lose the ability to do 2D
blits as fast as DirectDraw would have allowed right?

OK… but does this mean that the OpenGL hardware drivers also rasterize
slower since they do not use DirectDraw but GDI? I read somewhere
that the OpenGL Drivers do use DDraw and that’s why you can’t use it in
your own OpenGL code - kind of ironic, however in SDL_dx5video.c there’s
a comment there about using GDI for GL with a corresponding ‘Yuck!’