keysends are directly between lightning nodes that allow for accepting keysend payments.  You're basically paying to a PUBKEY as desination

lnurl is for sending to an ACCOUNT on a lightning node. Here you've got a username@server identity and talking to a web server requesting it to provide you an invoice to pay based on parameters given. 

 #Sphinx has Keysend don’t believe me ask Turiz 

 Thanks Vic! That’s a perfecy clear answer. Much appreciated 🙏⚡️