Thanks for the feedback! This is certainly a concern and one that I've tried to avoid by focusing on receiving (forwarded) email and not sending for the following reasons:

* Easier setup - nothing to configure and you can keep using your existing email setup. Using email clients can be very difficult for some people, especially older folks, so I don't want to make their lives harder by forcing them to learn something new.

* Less maintenance/upkeep - not having to worry about storing/sending/retrying means that users have a better UX.

I'd love to easily integrate sending from the custom email, and I may add it in the future for the power users, but I think the cost/benefit of it right now just isn't worth it so I'll keep things Simple©.