Thanks for raising this inquiry into the differences between the normal place template and a community template. The first is for your individual use in a particular place where you have administration over, while a community template is available for use across the entire community as outlined in our documentation:
Note: If you have Community Manager rights, you can save Place Templates as Community templates so that other people in the community can use them. If you're not, only you will see your saved templates in My Templates.
If you've created a template that you'd like to share across your entire community, it may make sense to simply share it and make it available for others to use.
I hope this has answered your question. Let me now if you need any further clarification.