If I understand it correctly, the main argument in favor of tagged templates is that it doesn't require any changes to the js engine and that is why it will be way much easier to push forward. Browser implementation should be quite straightforward and it will be possible to implement a semi-efficient polyfill.

Personally, I don't think that it will have any significant impact, everyone will continue using React,Vue,Svelte and it is highly unlikely that they are going to adapt this new API.