Why would I use ANY cellular data while connected to wifi?

Question

Just picked up my (pre-ordered) iphone 6 at the apple store this morning and spent the last few hours transferring everything over from my old phone.  I've been on my home wifi the entire time but noticed that I used 3MB of cellular data.  I know that's not much but why would I use ANY cellular data while connected to wifi?

unknown · Accepted Answer

Something's just cannot be done through WiFi when the device its self needs to have information sent to it.

Cellular will pop on when necessary. My iphones do it but like you I use around 25 megabytes in a billing period.

Good Luck