> since people need to engage over several months to get value out of the advice

This is false.

> I find popups annoying too

I do not believe you, if you did you would know that often the first response to popup annoyance is to close the window.

What do your analytics actually say happens when that popup shows? It will show that I was reading your article up until that appeared, then I entered garbage for an email and closed the window.

Will my email GoF##k@yourself.com be counted as a success or failure for your popup?