With PoW, one needs enormous computing power that results in high-energy consumption. This may not be desirable. PoS overcome this by providing an alternative approach called the stake of the user. The user possessing or owning highest digital currencies (or some asset) gets a chance to create the block in the blockchain network. So instead of investing in high power computing nodes, one can rather buy out cryptocurrency (or own assets) and increase their stake to validate and create a block of transactions.