When self-hosting, is there a good reason why not to run the core on the same server as the backend? I'm using a DigitalOcean droplet which will run my app backend, supertokens backend and I'm thinking why not run the core there too?

you can. Nothing is stopping you from doing that

Cool, was just trying to understand why all the examples have this decoupled. If there is no reason not to then great. Thanks!