Don't be influenced by the low rating. I tested the Add-on, and it is extremely functional. You create a folder on your hard drive or anywhere else you prefer and place all the .blend files to be used as templates there. Then, just go to the Add-on settings and add that folder. It's very easy and fast.
While the add-on is fully tested before each release, on multiple OS(s), and it was working fine in the last (v1.6.0) tests too, i can't rule out problems for edge cases.
If you are willing to help me make the add-on better for everyone, it would be useful if you could open an issue on the repository with some more details (about your blender version, OS, and eventual error messages you see in blender while having problems), so that i can try to reproduce the issue and work on a fix.
Custom Templates
Don't be influenced by the low rating. I tested the Add-on, and it is extremely functional. You create a folder on your hard drive or anywhere else you prefer and place all the .blend files to be used as templates there. Then, just go to the Add-on settings and add that folder. It's very easy and fast.