Yes, because it has no private key when we use wallet like coins.ph. There are many hackers in this cruel world so please take care of your bitcoins, don't let them hacked your account.
if you wanna have a better security, i would recommend to have a multi signature wallet (the address with prefix of 3 instead of 1). in case of possibility of being hacked, they need certainly large amount of computing power which consumes all the possible energy in the Earth as there are more than googol (IIRC) of possible combinations and not all the private key is valid for bitcoin address.