Pos wallet is a good online wallet,you cn also use an exchange wallet but it is highly recomended that you run a desktop wallet to keep majority of your coin,so you can have a back up of your coin in case any incident happen,do not put all your eggs in one basket too.
Those who refuse to heed the warning are going to get burned. I posted warnings a couple times in the past about how they scam users (and multiple others have come forward with the same situations). If you trust PoSWallet, you're going to lose everything.