"It's too bad nobody here has an IQ greater than my dog."
First, make your point without *****.
Second. There is indeed an increase in the prices, but since the increase is different according to your level, not everybody pays 1.60. Triple diamond pays 1.10 per card and there's a discount for purchasing the new cards within 7 days from their release.
Decimals then are just another way to reflect the increase that is a lot more practical than making the buy page a mess to understand with different prices for everybody.
Also, there was a big period of time between the past carousel discount system and this. So members had the chance to use their existing credits before the rise on the prices. Credits didn't devaluate, prices went up, the value of the cards is what it is now.