Well,

is one of those elements that can create a startling amount of quanta (Solar Shield, RoL), and with Refractive Mist, a

/

duo could take advantage of ALL of Water's strengths in a single deck, which is really the point -- to allow

to have all of its toys at once at the cost of requiring Light quanta and a specific permanent in play to do so.
Also makes Rainbow Nymph decks much more reliable, as you'll always have the quanta to activate them.