I didn't think this was working until I read this:
It's nice that you found a way to use the WordPress native search form text box to then use Google CSE for results, but I didn't think it was working because the output looks like a WP results page. Perhaps you should be clearer about this in your documentation, and then fewer people will assume your plugin is broken.
Unfortunately, this plugin will not be what I'm looking for if I can't use the monetization capabilities of GCSE. Is there a way to change this? Other plugins add GCSE to WP with results pages that monetize, but they may not seamlessly integrate into the existing WP searchform text bar, which is a nice feature. Could you explain a different way to configure your plugin to achieve this, or would it be much too complicated?