you also avoid the collusion scares that happened last year with SSW and SSB where if the group draw was a little different either SSB or SSW would have intentionally lost games to get 2nd in a group so they wouldn't play in the semis, honestly riot got pretty lucky.
Going to relegations makes a team ineligible for the worlds tournament. That's why it was so important for C9 to finish 7th, 8th place finish would have meant not only them going to relegations, but also losing their chance to go to worlds.
That was literally the worst teamcomp I've seen in competitive. I really couldn't see how FNC is gonna win, OG played so badly and they still couldn't win but in the end that tristana just didn't give a **** as they had no way of engaging on her. Against an equal team with that teamcomp they are literally less than 5% to win.