According to uMatrix, loading tildamail.com results in a cookie request from gstatic.com. :-/
I'm not a web developer, but cookies tracking static contents don't make intuitive sense to me.
I am interested in their idea, even though there may be some disconnect between the marketing site and my idea of privacy.
Even General Michael Hayden admits: "We kill people based on metadata." Most people don't realize protonmail can read your metadata. But Tildamail end-to-end encrypts all messages and metadata, and is gives you power over your own data and privacy with decentralized storage: https://www.tildamail.com/