Most important use/function of these dice?
Making the manufacturer lots of dough.
Meaning they're going to get more out of selling them to you, than you're going to get from buying them.
Lets make a list of some of your other purchases where equation holds true...
False advertising! Headline is transparent rainbow dice, but when you get to choose your 3 sets, the rainbow option is only opaque! These are NOT the same. Opaque are way cheaper and more common. The price is bad too. Scam.
Since nowhere in the description does it bring this up, these are Hedronix Dice which are available at D20collective.
I have several and I've been genuinely disappointed in them, most don't match their photo colors well, they are very lightweight and slick enough that they usually slide rather then roll on felt or vinal playmat.
MoosefordMine are holding up fine. They've made it probably 30 miles of walking loose in a dice bag without wearing any worse then the Chessex set I got a week later.