This makes absolutely no sense strategically.
It has been established already that Ketil is willing to provide high quality tribute to the crown. He has no plans or intentions to deny this or to foment any possible rebellions. Canute as king can get fill his treasury from other successful farms from Denmark, why go for the one that has already submitted to you willingly, with precedence? Are his lands that good that no other piece of danish land can compare? I find that hard to believe.