Both the PoW and PoS system have their own benefits. I don't know much about these, only know what PoW and PoS is and a little of the basic differences.
I didn't understand one difference between these 2, which one is most decentralized? How? Please share how exactly PoW/PoS is the most decentralized.
Both of them are decentralized but i will give you one example where it may be easy to understand.
POW requires the mining computational power and the difficulty increase it will require more power. So it become out of reach of the normal miners and only those who have mining farms are able to mine it. So with less people mining, the more centralized it gets.
POS is different in a way that you do not need any hashing power but more the coins you own the more benefits you will get in staking. So in this case if you are more wealthy then you can control more the shares which will also supports centralization to some extent.