I wonder the same thing. What’s so different than your own vps and using lxd to create a container. Make two bash aliases and wow you can go in and out quickly and recreate it with one command.
If it helps: Jerome has been working for a couple months on a local, open-source Rust version of Sprites, so you can use the same DX with your own infrastructure. We just think this is the right "shape" for modern sandboxes, wherever you actually run them.