'Dark mode' as a plugin for website owners

Coming from the dev scene, dark mode is getting more popular in any of the apps and sites (https://www.searchenginewatch.com/2020/09/30/why-dark-mode-web-designs-are-gaining-popularity/).

As a Saas owner, I know that some users would love to have a dark mode. But as developer resources are limited, most of the time another priority is made. So adding a dark mode to your site which is just plug-and-play sounds attractive to me.

I've just worked out a prototype. Simply add some code to your site, and your users can switch to dark mode if they prefer.

Question: Would you, as website/Saas owner, pay for such a plugin to offer dark mode to your users?

Would love to hear your thoughts.