Going into more details for how this works, we intercept communication between the CPU and the GPU so only GPU code and commands are sent across the network to a GPU that we are hosting. This way we are able to virtualize a remote GPU and make your computer think it's directly attached to that GPU.
We are not copying your CPU code and running it on our machines. The CPU code runs entirely on your instance (meaning no files need to be copied over or packages installed on the GPU machine). One of the benefits of this approach is that you can easily scale to a more / less powerful GPU without needing to setup a new server.