What's the point of our devices becoming so powerful?

We all know that consumer devices (our phones, laptops, desktops, etc.) are getting more and more powerful each day. A few years ago, 2 GB of RAM in a smartphone was a pretty big deal. Now we dirt phones with 6 GB of RAM, same is the case for processors.

How much of this performance do we actually utilise? What do we do with this much compute power? The most intensive thing an average person like you or I would do is play games (or mine cryptocurrencies). Most of the time, our devices sit idle, doing nothing, wasting all that compute power.

What if there was a way to provide our devices' compute power to someone more in need. You could say we could rent our devices or something. But hey! nobody wants to give their device to a stranger. You shouldn't, it is yours, you paid for it with your hard earned money. What if we could rent only our compute power to someone? We wouldn't have to move a muscle, while our devices, that previously used to sit idle, would now do someone's work on their own, and we earn money while doing nothing.

How feasible is this? What are its security implications? Would we be okay to increase our energy usage (and consequently our carbon footprint) just for a little rent money?

All these questions really interest me and I would love to talk about them.