If elves like Aurelia are easily over 100 years old while looking fairly youthful, then what does that mean for Lily? Will she grow up until puberty at a human pace and then remain youthful for hundreds of years, or will she remain a small child as Weiss turns into an old man?
I guess Sieglinde kept her glasses because she intended to keep that "cute look" as something special only for him.
As much as I prefer Holo, she has to show up some time to keep her stocks going among the readers. She's at risk of becoming a background character at this rate if she hasn't already.