@MrGreenWithAGunLess cheaters, stronger anti cheat, stronger leave penalties, Allies who actually play as a team rather than being as suicidal as pubs players.
There also tends to be more living squads per ring than in Normal non-event pubs.
Half the time there's only 7 squads left in duos, but 12 squads left in ranked, at the same point in ring closing. Second or third ring.
Plus, since people stick with you more often than in pubs, you get to respawn them like crazy if you need to, rather than being abandoned like in pubs.
I get to make more full squad top 3s there than I do in pubs, because half the time everyone leaves before 10th and I'm left to survive on my own, in which I normally relent to ratting because 3v1s aren't fun. Normally making second because I let everyone kill each other and can't hold my own against the last squad.
More Secure:
Less cheaters
less abandoneers
more full matches
more fun
ensures everyone is in the final ring, rather than being alone.