It is a truism, Norwegian nacho pizza aside, the less is more when it comes to pizza. I discovered the potato pizza (which was indeed blanca, but I've made it with tomato and also good) in the US, but delivered by actual emigrant Italians, not the ones four generations removed.
Made at home, you have to get the potatoes right so you don't end up with mash on top of your pizza, which depends on the vagueries of your oven.
Hold on, did I just say mashed potato pizza. Mmm...