This is the edge of the gambling developer against the players so technically if the house edge is very high the chance to win on that gambling site is very low which every gamblers don’t like. This must be balance since gambling site wants to create profit as well same as the players. This is so easy to understand mate, and also important to know before you gamble.
I saw a thread in this board not that long ago asking what people thought was an acceptable level for a House Edge and while there was some discussion the consensus seemed to be in the 3% to 5% band as an acceptable House Edge