CoinOS is just a fast way to take the payments on LN, then you withdraw. That's it. If you want to use it more extensive, you can create your own keys (for onchain wallet) and have total control (in case CoinOS is down). Also you can create sub-accounts for employees if you want, so they cannot have rights to move the funds from it, just enough to charge (create invoices). But CoinOS should not be used as main way to store all your BTC.