In POS systems the block validators are usually called Forgers, and it usually works by them sending their coins to a smart contract address (or something similar), to "stake" it, so they stand to lose their coins of they behave dishonestly.
PoS does not require a smart contract. There are a lot of cryptocurrencies out there that use PoS (or some alteration of it) instead of PoW.
POS systems do not need have mining computation so they don't have to give time for a block solution to be found. Therefore, the block time can be reduced which usually increases the number of transactions the blockchain can process.
When staking your coins in a PoS system, you also run at risk of minting orphaned blocks. Therefore adequate block intervals are still necessary. Also note block intervals is not at the heart of the scalability problem, but rather the rate of blockchain growth. This problem is not circumvented by smaller block intervals.
PoS ! is it illegal or piracy or something like gambling...
PoS miners use their own coins for attracting fees of transactions ?? it's not clear enough for me.
PoS has nothing to do with piracy or gambling.
Consensus algorithms always require some sort of scarce resource to make potential attacks as expensive as possible. This could be processing power (in the case of PoW), trust (in the case of banks), coins (in the case of PoS) or pretty much anything else.
In the case of PoS, various users in turn get to decide whether a transaction is valid or not. If they decide rightfully, they earn a reward. If they try to cheat the system, they lose their stake. In PoS you basically vouch with your capital (ie. your stake) that what you claim is correct. That's pretty much it, in a very oversimplified nutshell.