If you look at the pokemon disassemblies, a lot of data is baked in. I'm thinking if homebrew toolchains integrate C23, it would help with performance compared to more standard C99. Every little bit helps on low spec platforms though I don't think this would help much with NES embedded graphics, but there is a PCM channel for the APU and you could #embed a wav file. I can see uses for other consoles though, GB, GBA and even 3D consoles. It might help with memory efficiency.