I worry about things like this trivialising the difficulty of the past. Something like this is more like modding a game than making a new game in terms of tech. It makes it seem like it's really easy to make a Game Boy game, when the creators of this put in heaps of work (more than just making a game) into making a tool that gives people the ability to reskin their base game.

Homebrew that's designed to run in an emulator isn't the same as running on actual hardware either. In the past people had to think about things like how to fit a 20hr RPG into less than 1MB. Now you could make tile sheets for each room because the game can be much shorter. Other things like how art assets can look good on a modern LCD monitor when on an actual Game Boy they would be a blurry mess also contribute to a misunderstanding of retro games.

People already have an unrealistic view of "retro" games because in GameMaker or Unity it's easy to have 1000s of sprites, shaders and 32bit colour(You can even have HDR sprites if you want) when that isn't possible on the actual hardware.

I'm not trying to hate on GB Studio it looks great, just some thoughts.