Same for me.

You can but last time I used it the first option you were presented with was giving keybase your key. I don't know if that's changed years later because I closed the app at that point, I wasn't interested in using or encouraging others to use such a thing. The guy pointing this out was downvoted and I frequently see the fact that its possible to not give them your key presented as somehow making it acceptable that they ask for it.

Keybase would prefer to handle your private key too. You can work with your key offline too, but you have to be aware that this is what you want when setting up- and it's very much not the happy path, so the site will not fully work as you might expect.

Not faulting them, they provide the steps needed, but it might be annoying enough for some people to start uploading private keys.

I'm talking about uploading your private key. Obviously, it's required if you want keybase to sign on your behalf.