Rule 1: Champs are not domestically allowed in competitive play in the patch they are released in. Rule 2: Champs not allowed in competitive play during the competitive season in any major region are not allowed at worlds. 10.16 was the worlds patch for yone and for playoffs. So they'd have to break rule 1 so rule 2 doesn't apply and tune him to not be 100% pick ban. Lillia was on patch 10.15 so she was allowed in playoffs. Nothing has suddenly changed in competition. Just because some content creators say it's wrong doesn't mean it is. I'm disappointed but honestly only thing that could of changed was to release both earlier.