Oh, I see, we're just doing Diffie-Hellman but with elliptic curves? Ok, that makes much more sense... it was confusing for the article to compare it with RSA instead of vanilla Diffie-Hellman.
“Encryption” with elliptic curves is just ECDH and then using a symmetric cipher like AES.
Signature is a little more complicated. It’s not just “encrypting a hash”