Proof of stake rewards those who have lots of money just for having lots of money, the more you have to stake the more money you can extract from the users of the network, just like our current system. It has a centralizing effect and leads to the devaluing of the units within the currency as it doesn't feed new energy value into the network and only siphons the current energy from the network, again just like our current system. It creates new tokens with a marginal cost of production of $0, and everything trends towards the value of it's marginal cost of production. Just like our current system.

Proof of work creates new coins in exchange for ever greater amounts of the time effort and energy used to create them. The amount of money individuals have within the network doesn't matter as anyone anywhere can mine Bitcoin, which has a decentralizing effect. The value of the network is not divided further by the issuance of new coins as the value of the work is absorbed by them. The continuously rising marginal cost of production of new coins provides an anchor on the price that is connected to the real world, dragging the price up over time relative to the excess global energy fed into it.

Proof of stake is a zero sum game and a ponzi scheme, proof of work is not.