This is great to see! After learning that there is no clear roadmap for WordPress moving away from the old, insecure PHP versions, I thought about creating such package myself.
Yoast SEO definitely has a big enough user base to make a difference, and I hope other popular plugins follow.

I do see that it's an annoyance to get such a notice on your site, but I bet most aren't even aware that they're using (and probably paying for) an insecure version of PHP.

By using Freemius in Content Aware Sidebars, I can see that less than 2% of the sites using the plugin runs on PHP 5.2 and more than 50% are on PHP 5.6+.