That's a misuse of a tool. A sandbox is for specific testing purposes, making them the default limits program usefulness. From a network/biological perspective we need reasonable ways to prevent and fight infection. Focusing soley on prevention leaves you powerless when you are inevitably infected. Infected computer can take multiple strategies the most interesting of which is to waste resources so the virus cannot self replicate and transmit, one strategy is tar-pitting.

I want a program that can delete or encypt all my files. I want a program that can 0 or encrypt any chunk of memory. Otherwise I'm just buying a useless toy not a computer.

Sandbox is for third-party software. You may run the program you wrote yourself without a sandbox but running a random program from Github unrestricted is pretty dumb.