Amy, I can't comment on whether the appearance of the faucet will work, haven't seen enough of your bathroom. But my sis just installed faucets she can't return which are very tall. She discovered too late that the mirrors she intended to put on the wall above the vanity can't be used because the faucets are so high there's not enough room between the faucets and the light fixtures, which are also already installed. Just a caution, because your faucet looks pretty tall, that you need to be sure you have enough room for what you want to do above the vanity.

My gut feeling is that if it is made for a kitchen, it will be too long - front to back - for a vanity. You could replicate it by reshaping a wire coat hanger and then taping it to the vanity.

The flow rate for kitchen faucets is usually quite a bit higher than for a bathroom faucet. I suspect it will be very splashy.

I did it once in desperation because I couldn't find an 8" bathroom faucet at the time, small town, other factors. It was quite the BEST bathroom faucet I ever had. High enough to wash my hair at the sink if I wanted, could swing it out of the way when I wanted, and it totally worked.

It was an older bowl, and I have noticed some of the newer bathroom bowls are pretty small. If I were you, I'd place my granite on the vanity, not sealed down, stick the faucet in the holes and see if it will work. That would tell you the "true" story.
No one will know it's a kitchen faucet, they'll just think you are a superior decorator, and wonder where you found such a bathroom faucet.

Like marg, I'd try it first and see what happens. I don't see where a mirror behind it would be an issue since some of my mirrors are behind faucets. But, if you have a large mirror frame the bulk of the frame could cause a problem

Most faucets can have flow restrictors installed and many decorators now use outdoor light fixtures indoors, so I don't see why you can't use it if it fits and the look doesn't overpower the vanity. IMO, the one thing you have to check is how the water flow hits the sink bowl. I believe if the vertical line of the faucet is too far beyond (in front of) the drain you'll have more of a splash issue.

How deep is the sink basin going to be? That's the big issue.

I think you need to have a basin that's proportionate to the size of this faucet -- for the scale to look right and to avoid a big splash-back.

I have to disagree with one comment: Unless someone has never seen a faucet like this (in a home, in a decorating magazine), it does scream "kitchen faucet," -- but if you like it, who cares. Try it -- you have to see it and use it in place to know if it's going to work for you.