Funnily enough the blank page extension was made by a Chrome developer, so I assume there were some team internal tensions and those who wanted to keep that feature were overridden..
It will change the artwork daily by default, but you can change the settings to change on each new tab.
The reason I started using something like this is because the "top sites" I visit is not something I want on my screen if I'm showing it to other people.
OP does have a regular page you can use though: https://hello-extension.netlify.com/
Not commenting on your plugin.
I did not notice any typing / suggest box lagging or performance problems and I do not have the strongest laptop. The same thing for some extensions that I used before and rendered background image.
AFAIK these things should also run in separate thread, so lag in the web page should not freeze omnibox.
One that I love: https://chrome.google.com/webstore/detail/githunt/khpcnaokfe...