Bitmap fonts have the benefit that they are much faster to render and take less video memory. It's only 2 textured triangles per character, whereas outlined character can be up to 100 tris. I think it was first Nehe tutorials where i learned how to use WinAPI and OpenGL to create the font 3D models, before i looked into bitmap fonts. Those tutorials save characters into displaylist. I think not even glut was needed, just some simple existing API function.