Users with JS disabled on their browsers may not be an issue, but SEO certainly is.
Yes, Google may now index pages that are generated by JS on the client, but not all search engines do that.
And all other things being equal, Google ranks faster loading pages ahead of slower ones. So which page do you think that Google is going to rank higher? A page that comes down from the server with all of its HTML already in place, or one that has to download a load of JS to generate its HTML? Keep in mind that for the latter, the JS has to download, parse then execute before the user even sees anything!
Users with JS disabled on their browsers may not be an issue, but SEO certainly is.
Yes, Google may now index pages that are generated by JS on the client, but not all search engines do that.
And all other things being equal, Google ranks faster loading pages ahead of slower ones. So which page do you think that Google is going to rank higher? A page that comes down from the server with all of its HTML already in place, or one that has to download a load of JS to generate its HTML? Keep in mind that for the latter, the JS has to download, parse then execute before the user even sees anything!