Wagyu is all about fat.
The beef's high level of fat marbling is not just any fat but it has a high proportion of monounsaturated fats with high levels of omega 3 and 6. The soft low-melting point fat is therefore healthier than the regular saturated kind.
But I love Wagyu not for this health reason. People who know me or eat regularly with me know that I am someone who "Live to Eat" rather than "Eat to Live". I love Wagyu for its depth of flavour and melt-in-mouth texture and tenderness.