This is the kicker when it comes to IG88. As stated above he is very easy to kill even at 7 star. So putting him in a team that can't use his chance at AOE ability block his value dramatically decreases. But if you put him in a full AOE team with Boba his ability block can be the cornerstone of a full two round ability block as IG88 has high speed he will go first. His % + Bobas % means theres a good chance for two rounds the other team will lose 60-100% chance of firing off any ability for two turns. If that happens against a full AOE team the collective damage is so great if the healers can't pop a heal more times than not that team doesnt make it past the 2nd turn. Of course the ability blocks dont always land so its not a beat all synergy. But Ig88 is there because most of the time they do.