Its the same system most TCGs use. The more wanted the card the harder it is to get though unlike some TCG UR cards are not that hard to get. I have pulled a few #Anhutt but I have never pulled a shiny charazard and I brought way more Shining Legends packs. (Same with chase Yugioh and MTG cards)
Can it be annoying, it can be, but its just one of those things TCGs do to get people to buy packs, and to give people some high value cards you need to have cards for people to chase.