User blog comment:Kaido King of the Beasts/Chapter 866: The Iron Non-Giant/@comment-31434191-20170525204301/@comment-31434191-20170526181945

At this point, yes. It undermines a good portion  Emperor credibility that has beem established for the longest time. They all are supposed to be on level with Whitebeard, so one going out now (when Luffy can barely match a Sweet Commander and Bege being one of the weaker direct combatants of the Supernova's (reallying almost entirely on numbers and surprise)), even to a surprise attack, is just a poor show. If she dies LATER, when Luffy and his crew have grown in strength (or have the Grand Fleet to even the numbers) then it wouldn't be a problem.

Plus dying without a big head-on battle is REALLY anticlimatic for One Piece, especially since this is the FIrst Emperor they're facing (even if Oda tries some BS handwave like "Oh yeah, she's the weakest Emperor", etc).