why do keystones still exist

Riot wanted to add these to make it so you can "switch your masteries around" or something of the sorts but i pretty much take the same page with the

same champion maybe switch around 1 thing. some champions get nerfed because they are too strong with a certain keystone (Nidalee strength of the ages)

They aren't good for the game and add a lot of balance problems make new masteries that aren't so broken this is probably the worst ive seen league imo.