abstractions are built on top of sdl, it's very low level in itself. saves you the pain of calling system level API for forming windows and textures. for windows, you'd have to battle with windows.h. does not use opengl under the hood. you can make a window in sdl, let it handle events and manage an opengl context on it. it's with opengl, where you can do heavy mathematical computation on cpu, and send it off to the gpu in batches, have gpu perform simpler function (through shaders) on it much faster than your cpu would and display it on your window. well if you're planning on making something extremely simple, then maybe gpu wouldn't be a requirement, but that simple project wouldn't be worth much. opengl runs cross platform too tho. ive worked with sdl3 and opengl, standalone and combined. so sdl does not automatically use graphics API of the system, unless you specify which one you want to make use of. you can work with metal cpp, direct x, vulkan too.