- PoS is generally seen as more scalable than PoW due to its lower energy requirements and potential for higher transaction throughput.
I don't think this is true at all. No matter what consensus mechanism you use, you still gotta pass the tx data around the network. For example, Ethereum switching from PoW to PoS did not improve transaction capacity. And Vitalik Buterin stated this many times because there was an assumption that PoS would improve tx throughput. It doesn't do that.
For example, if Bitcoin switched to PoS (which will never ever happen), that wouldn't do anything to increase transaction throughput. Only by increasing blocksize or decreasing block time would transaction throughput increase. Or changing some parameters of transactions to make txs more efficient with data or sneak more data in as some Bitcoin protocol updates have done.
All PoS does, compared to PoW, is switch from hashpower being used to confirm blocks, to staking the token supply being used to confirm nodes.
PoS is inherently more centralizing that PoW, and people often argue it is a weaker consensus mechanism than PoW as well. The positive is PoS doesn't use an electricity race to add blocks, but then it also doesn't provide the benefits that Bitcoin's PoW provides to society by using wasted and stranded energy and solving energy imbalance issues in the world.
But PoW is mostly a winner take all game. The dominant PoW blockchain is going to command the lionshare of hashpower (or at least does in reality since Bitcoin dominates), and so all other PoW blockchains are tiny compared to it and are inherently attackable if miners switched decided to switch from Bitcoin to other PoW chains in order to attack. Double spends are fairly easy to do on every PoW chain other than Bitcoin, because they are all tiny. This is somewhat negated by some PoW chains using different algorithms which prevent hashpower from crossing over (I think). But still, there is really basically only a need for a single PoW chain, and that of course is Bitcoin.
In light of that, PoS, even though it is inherently more centralized and weaker than PoW, makes sense for altcoins because they would all just be really weak PoW blockchains anyway. And they are already run by companies and founders and have premines and everything so they are fairly centralized but distributed products to begin with, so having a somewhat centralized consensus mechanism is simply in line with the rest of their design.
But yeah, OP, PoW uses electricity to compute hashes to solve a mathematical problem to add blocks to the blockchain, with all the miners competing to solve the problem for each block, because all rewards for the block go to the successful miner. While PoS has owners of the currency "stake" their tokens and then the block earnings are dolled out in proportional share to the staking network based on how many tokens are staked by each staking member. There are different ways to set this up. For example, Ethereum makes it really hard so that has caused Ethereum staking to become super centralized because everyone basically just has to use one of a handful of staking services.
