[IanCal]

I'm not filled with confidence when visiting a secure messaging app site that fires off warnings when visiting the https url.

[XorNot]

Of course HTTPS is not at all secure due to that central source of authority enabling easy large-organization MITM.

[IanCal]

If the problem you're solving is bringing E2E encryption to the masses, then starting with a site that brings up

"Your connection is not private

Attackers might be trying to steal your information"

as the very first thing I see is not really leaping over the first hurdle.