Why? Because of the time and effort it saves me.
I make around 1500 searches per month. If it saves me 3s per search (I'm 100% convinced it's actually way more), that's saving me 75min in a month. I'm paid more than the unlimited plan per hour.
But it's hard to put a number on how much it's worth having a search tool that is algorithmically unbiased (except against ads), that actually works, and that denies big tech my data.
It is true, though, that they went back on their promise to grandfather current customers. That will stay in my memory.