The link to the github repo is located in the code you paste on your own website, so you already host that part yourself. The only thing someone could change if the account is hacked is the contents of the image.
If you're using the hosted version, you have no idea whether or not the modules are being updated, which versions are in use, etc.
Having control of your environment gives you the opportunity to be more (or even less) secure. It's important to fully understand the risk / potential harm that outsourcing that responsibility to random persons can have.