@olamundo@red.niboe.info @Tutanota "Your email is your home address in the internet."
(well said)
Without bashing Tutanota - that part about "Your email is your home address in the internet." is frighteningly true and a big technical point from which everything almost stems (using S.T.E.M. lol) and all the people you're connected to also (which in terms of surveillance down the line is like betraying / leaking names they will eventually map / hunt down.
So in this case it can seem VERY innocent to 'just sign up' but if they give themselves permission to share and do whatever they want with your details and connected things, then all it takes just one or two services (or one parent company) pimp the details and to spread it around.
The reality is that it's their house space and it's far from mutual. It's worse as time goes on.
It was always cheating ourselves by having such things.