1) Mozilla is generating a stock set of components that you wont have to "scour" for. 2) The components can be easily included using an app bootstrap builder that the Mozilla Marketplace dev hub will feature 3) You write the tags like you would any other in HTML, there is not complex copy or paste operation... 4) You can use components without modifying them, #4 is a red herring
Another huge benefit: the polyfill is 2k compressed composed of pure, library-independent JS