Fleur's concerns were certainly not her paranoia speaking—the three elders were exceedingly powerful and on the verge of unsealing their pineal gland.
When that happened, their abilities were most certain to rise to new heights.
Barring Fleur herself, they were her strongest fighters, but that also meant they shared the same problem as Fleur—that being the Eternal Pills were out of reach.
Without it, they were not likely to live more than two hundred years, which was already way shorter than