Consider that most people use shielding skills and that his chase causes Blindness are just the start of the good things to consider about WB Asuma. Specifically, if Earth Main is using his shield skill, your opponent would have to break through that shield and damage any character in order to remove WB Asuma's skill of increasing Attack and Ninjutsu.

AOE Mystery
Blind
Auto hits up to 4 front targets (clone killer) in GNW or Ranked and can chase his own auto w/ Blind
40% damage buff to anybody with 100% health. As an Earth Main, you add another 30% for anybody with 50%+ health. The damage adds up.
20 Chakra first turn is amazing if you use an interrupter and someone with a barrier or a healer. Kabuto clones + Iruka interrupt is now possible or a healer mystery like Kurenai shield or Sakura heal etc.

This filter makes it so hard to give long explanations. The "increase stats just for full hp members" and front ROW attacking standard is why he is good. I wouldn't underestimate his AOE mystery either, while on the contrary, I believe his chase to be his weakest trait. Having an extra 20 chakra round 1 means you c*e 2 mysteries and possibly eliminate 1 ninja or control 2 ninjas into round 2 (If you immobile after a character standard attacks, they will stay immobile next round).

He attacks full row. What is very good, especially in team fights. And his dmg is pretty high as well

Great for nine tails also.

Asuma WB is also very good to thrill the lightning formation too since his AOE can deal really good damage. If possible, have him soon before they downgrade him to a 2 star ( in the future , with new updates he will) . And people still use him a lot in CN servers .

He is good for killing bunshin..

9 tails and he is good in some leeching comps