[dnamlin]

An Ethereum address is just a public key (which, as the owner, you also have the private key to). You can make one, and sign messages with it, without touching the blockchain or sending any assets to it. So added complexity is -necessary- only to the extent you wish to involve those additional ways you can interact with the blockchain (that you can't using GPG or SSH keys). I'm saying this in principle of course, granting the current lack of convenient utilities/CLIs for operating this way.

I would speculate that there are probably already more people who practice decent opsec for their Ethereum keys than for GPG & SSH keys. Soon it won't be close!