You can read the emails I am composing, but not read the emails I receive? That is better, and I could always compose sensitive emails in gmail. So possibly I'd give this a shot with my personal email.
I'd also like to use this at work, but Boomerang[0] was deemed not allowed, so I would imagine Darwin would also not be allowed.
I'm guessing Darwin stores the reminder data on its own servers? That doesn't bother me, most reminders are quite benign.
For reminders that maintain privacy, I would imagine one would need to write a browser extension that threads reminders into gmail. Which doesn't sound like much fun, but also a pretty primitive integration would probably be good enough.