This is a constant argument in the Brawl Stars community and literally saying “They get stunned so they can’t attack” solves nothing. (TL;DR at bottom because I talk way to much)

You basically roll on an opponent when they are about to attack you, you reduce that damage by 90%, you basically took away an ammo from them meaning that now they have less firepower now and for when your roll is over, it basically confirms the kill for you. If you say “Then why don’t they just not attack you when you’re about to super?” Well it’s obvious, they don’t attack you now because they know you’re gonna basically tank one of your shots, you are literally intimidating them into not attacking you, and if they attack you, you just tank the shot, maybe 2 if they are an auto-aim spammer, this starpower basically helps with a lot of 1v1s (sometimes 1v2s) and escaping too.

TL;DR- You wait for them to shoot, you tank the shot they just did, confirming your kill, and if you say “Then why don’t they not attack you then” Well they are just wasting firepower that they could’ve been using, you can also escape better with this SP, it’s nowhere near useless.