Thanks Johan! :)
Snack is a big group effort from lots of people and drawing inspiration from a lot of stuff that came before!
I made the original Snack prototype. It was inspired partially by RNPlay for sure (one of the best projects in the early days of RN!), but also JSFiddle and Codepen and every other interactive environment that I'd seen before like Smalltalk etc. I also just thought that the packager was too slow and fragile and I wanted to cut it out of the equation. That seemed easier than running a cloud version of the packager.
The prototype I made barely worked but you could see how fast it was to update, and that was exciting, so Jesse took it and made it into a real thing along with Satya.
More recently, TC along with Satya and now Nikki have picked up the mantle, adding a lot more reliability and the ability to include arbitrary npm packages. And Jimmy the intern made the thing where you can download a Snack into an XDE/exp project.
Watch out for more improvements coming along. I also am excited about taking the best parts of Snack and getting them into the command line environment and vice versa. Will take some cleverness and time to do this well though.