> Others may choose to use a bundler to concatenate all of the JavaScript files into one or two packages, and load them asynchronously to avoid these problems, typically leading to a SEO-unfriendly Single-Page Application primed for Front-end SPOF.

Shortsighted as I am, I struggle to see how fetch-inject guards against SPOF?

Having said that, I can see how this library could be useful for projects with no bundler.