nah, this "just a private key" argument misses the point completely. eth wallets drag the entire baggage of that ecosystem,gas fees, tokenomics brainworms, "sign this txn" anxiety,into what's supposed to be simple pub/sub messaging. nostr keys are lightweight, disposable, zero-cost... that's the *feature*.
once you make people boot up metamask just to post "gm," you've already lost 95% of normals. let alone the tribal toxicity when every profile pic becomes a token billboard.
plus, hardware-wallet nerds: export your nostr key to a trezor if you're *that* paranoid, nobody's stopping you. just don't force the UX complexity on everyone else.
build whatever you want, plug away, but don't be shocked if the crowd here just shrugs and keeps vibing without the eth circus.