I guess it's not super popular, but it's gaining steam as the go-to pick for "quirky" parents and I just don't get it. Of all the cute old-school names to resurrect, why Elsie?? Where did it come from?? What need does Elsie fulfill?? I felt the same way about Matilda.
I think Elsie is adorable! It's slightly quirky, with that vintage feel that the "hipsters" seem to love! Now I'm no hipster, but I do think the name is lovely and will suit a female of any age. Matilda is lovely too.
I think it fills the same niche as Liam and Kaitlyn. Variants on previously super-popular names. Perhaps for honoring purposes, perhaps just because Elizabeth, William, and Katherine seem dusty and boring.