Someone might give me a used iPhone 4s. Can it be used as a PnS camera without a SIM card ? The iPhone camera should be much better tha the one in my Moto G.
No experience with iPhone, so ...
Yes you can use the iPhone 4S without SIM card to use Cam only or as a wifi only device to use apps and such for gaming etc. But remember one thing. If you restore the iPhone or using iTunes update the OS or someone gives you a freshly restored iPhone, You will need to first use a MicroSIM to activate the iPhone once and then you can take the SIM out and put phone in Airplane mode (if you want) and use it.
But you will need a SIM card once to activate the phone after a restore or iTunes OS update. There may be a way to active without SIM but it never worked for me so don't count on that.