Title says it (almost) all, this allows to play retro-like-yet-recent games. Also, since it is just PNG with extra code, it can be allow to load it from the web like canvas content, not just install to local machine.
TIC-80 was added in update 0.16.6.1 along with LowRes Nx. The checkbox was marked on 28 Feb, I don’t know if it was my suggestion or not. If it is, then you guys work extreme fast to finish this.
About Pico-8, I don’t expect you to implement in the first place since that software is proprietary software, so I will mark this suggestion as complete. (If I can mark it)