That link preloads mithril in a web playground and you're ready to go in a couple of seconds.
You can even download and continue development locally should the need arise - without the gorilla and the jungle hiding behind it.
The biggest problem I find with that is if the template/tool gets some deprecated/critically flawed dependencies, for tweaking it can be ignored but not for production or critical systems.
Also taking the time to set up your project with what's just needed will allow to dodge a lot of bullets of breaking or useless dependencies, malicious dependency update tc.
That link preloads mithril in a web playground and you're ready to go in a couple of seconds. You can even download and continue development locally should the need arise - without the gorilla and the jungle hiding behind it.