I think the overarching issue is: Does relying on any sort of tier system to make in-game decisions actually make you a better player? I don't think I've made a single in-game decision by comparing cards' Qvist rankings. I make all my decisions based on intuition and experience, and I think all the top players do as well.
I think somebody actually pointed out on the Qvist ranking thread that the rankings are mostly just made for fun. There's just so much information that a ranking can't tell you: How many copies of a card to buy, at what stage of the game to buy a card, how your opponent's strategy affects things, niche cases that make a weak card good, etc. Looking at a list and seeing that a card you were ignoring is actually really good might be helpful to a beginner, but I'm not sure it's actually THAT helpful. A player could buy Governor solely because of its high ranking and still lose because they don't know how to play a Governor deck. It's not enough to know a card is good; you have to know WHY it's good.
Yes, I agree completely. I however, don't know all the ins and outs of card interaction, nor even their over all power. I think it could actually help someone like me. Yeah, I'll eventually outgrow it's usefulness, but I'm not at that point yet.
It would also be a good way to see where different types of cards rate in the overall META. Are gainers mostly rated as B's? Are attacks mostly rated as A's. What about sifters? Are they mostly rated as C? Are alternate treasures all over the board for ratings, or are they mostly A's? It would be a good way to be able to compile a bunch of data quickly.