It looks like this is just for static data files. To run a piece of memory as executable you'd have to explictly mark the page as executable with e.g. mprotect(2) on Linux. I guess there's nothing stopping you from doing that from Go also.
You still need an ELF loader, unless you're shipping shellcode. As far as I know, there's currently no great way to load an arbitrary segment of memory as an ELF, without doing some sort of copy (eg. memfd_create, write, exec).
