I think that is a reasonable statement. SDL includes other functionality like image loading, audio, etc. whereas GLFW is primarily focused just with getting a window with a graphics context for OpenGL/Vulkan/etc set up.
SDL’s advantage is that it supports more platforms (like mobile and Switch), and is much more battle-tested with hundreds of games using it, including Valve’s ones. Many people seem to use SDL for only windowing and input and seem okay with it.
