M2

What are the main differences when comparing the two technologies described for P4?

You can not connect if your in the middle of a country side, you can use 3g but it will cost some money on your phone. Also a picture message, this is not good it will give you a fuzzy picture that you can not really see.
Your phone can become a mobile hotspot if you wan't it to become a mobile hotspot  then you can connect to your laptop. Then you can get wireless anywhere and send pictures from your laptop, which will give you a clearer picture.