Hadn't heard of keychat yet. What's that for?
Discussion
It's what he was talking about in the OP. A browser with built in Nostr signing support. You can sign into Keychat using Amber, so it doesn't even have access to your keys.
Most Android apps support Amber too, so there is no need to spread your keys around.
Well sure, problem is I got Amber last not first... Generally speaking a new nostr user will just put the nsec straight into their first client. Or even have the client directly produce it. Chicken and egg ya know