Spells that target enemies and spells that target friends use different animations. There's a different kind of sheen to an enemy cast spell than a self-cast spell. Not to mention Blue Magic uses its own swirly regardless of element.
The swirly you see is the generic swirly for abilities, but lightning sprits have a special sparking animation to go with their casts for their spells, and so on; what you do see is -before- the swirl/spark, for a brief second, you do see the same purple-cast aura that a blm has when casting thunder for Thunder Sprites. So, if you look at the water sprites, you can see they do have an offensive cast aura that an aqua blue color.
The cast animation for Vercure and Benefic and Esuna has two colors--blue-purple in the center, and on the outer swirls, the same blue color as the water sprites use in their subtle offensive cast animation under the swirlies.
However, if you go to Il Mheg, and you fight undines, when they cast water II, they don't have the 'ability swirl' you describe. They have a bluish purple casting aura--the exact same blue purple in Vercure et al.'s cast aura.
What we don't see are the rainbow effects of unaspected spells, which contain hints of red and blue and green, as well as white--something you can see for yourself.
Except for Undines casting Water II, Sahaguin casting Enwater....Vercure (and Benefic) use a shade of desaturated silvery-purple-blue that shares more in common with the lighting on our job-switch animation than any Water spell. I'd sooner argue they're a unique color for "unaspected healing" (as opposed to the "rainbow" of unaspected damage).
They deal physical damage. Not 'unaspected' which is magical. You can test that for yourself with Embolden.The swords, meanwhile... deal unaspected damage.
Blizzard IV doesn't deal physical damage. RDM abilities do. Everyone knows this. Test it for yourself.And before you say "well they're stabbing you", Blizzard IV drops a glacier on your head and still deals ice damage, impact type ain't the determining factor. Contre Sixte's swords explode and still don't deal ice damage.
Our sword oGCDs are just crystallized aether. Stop imposing your headcanon as fact.
Claiming the swords are 'unaspected damage' when they're physical would be imposing 'head canon as fact.' And it is entirely possible to channel ice-aspected aether and deliver a physical attack. Samurai do!