The "Cup" is a lottery, yes. Also the teams that seem to spend a amount of T are "most favoured" in this kind of competitions since the CUP format is based on Q (which means that to get Q, you have to buy/pay for T to reach a certan Q-lvl).

Also if you don´t have a team that is composited of 7* or 8* there is no reason to be dissapointed if you get eliminated in a early stage, since the % to reach a semi-final or final are quite low and the prize money are a joke.

It´s better to concentrate on the CL & League if you want to "win and earn" something, since the CUP is more about prestige.