The reason Square Register needs access to your microphone is to "listen" to the Square Mag Stripe Reader plugged into your headphone jack. without that the app can not comunicate with the reader. The location/GPS is because square is a mobile payment solution so it is able to use your location to print on the emailed and texted receipts where the transaction took place and to mitigate fraud.
It only has access to these items when it is open and running on your phone or ipad. It does not connect to your pc camera or files.
go to that link
chose a product from the drop down. (Square Register)
Click "call us"
your code and the phone number will apear there.
It's not that there is an open camera taking pictures and an open microphone recording your conversations. It's that you gave the app permission to use it (unlike the old days when programs just had unfettered access to your computer).
The access to the microphone is how the square reader communicates with the phone hardware and then the app.
This is isn't some black market app you're illegally downloading that has a bunch of spyware in it, like when people pirate software. It's a program but a publicly traded company that would have been outed by the white hat hackers long ago if it was spying on you.
If anything, be more worried about your own government illegally listening to everything said on a phone call, or hacking into the trunk line of isps and intercepting whatever data it wants, "just in case they need to go back to it later."
