Welcome to the present
Your site is viewed on multiple devices, with very different screen sizes. Smartsites stretch and shrink so they work and look fantastic all the time.
People who don't speak english or require screen readers. Observable understands how to make your site accessible to everyone.
Smartsites are future proof and can be adjusted easliy as more devices become available to your users. Things are not going back they're moving forward very quickly. The time to upgrade your site is now.