Use a pod template file in a Deployment
Yes you can create resources (including pods) from a url yaml using kubectl.  However, just because you pointed to a remote url does not mean that the resource will automatically update.  You will need to either re-deploy when the remote yaml is updated, develop/integrate with a service that handles this, or look into using a tool such as helm to help manage changes.

It does not need to be avoided, you just need to know that it will not automatically update if the source changes.