POS is the same thing as if you would put your money in the bank and leave it there for an interest. So it has nothing to do with "mining". FYI
Well not really unless you are doing POS with a third party service. Real POS involves having a dedicated computer/server turned on 24/7 to also validate any transactions that are sent your way. So technically, yes, it is still mining, mining transactions at the cost of "staking" your coins in case you try and do anything something malicious.
POS could be the future, but until real coins like ETH implement it, i wouldn't decide anything yet.
No it is not. Your "mining" is actually supporting the network for free. And just like the bank, your share(interest) depends on the size of your stake. But, unlike the bank, the amount of risk is ridiculous.