It basically makes player to player trade obsolete. No one has any reason to go anywhere but the GE to trade. There's no bargaining, up-selling, trading in random banks, player made trading zones, etc. Things that people kind of miss from the original game. One of the biggest things OSRS lacks is player to player interaction, and the GE is a big part of that.

Its one of the most important things in osrs now.

Well, it's the easiest way to trade. This doesn't mean it's good for the game. If they made a new weapon that costs 50k and had twice the DPS of the whip, it would be "one of the most important things in OSRS", because everyone would be using it. That wouldn't make it a good item, though.