I like the tablet because I can watch videos, read books, mags in bed without moving my laptop. I don't find watching video on the smart phone too great. It's just too small to enjoy & it's not a reader.
I mostly use the smartphone to text, take pictures, but I don't usually read my Email on it.
Do you Need it? Well, that's what I thought that I don't need it, but once I got it... I really love it. The 7" size is big enough to enjoy video & small enough to take everywhere.
If you have wi-fi & your friends have it at their houses you can use theirs & it's private. The one we have at work is also private.
If wi-fi is not easily available to you, then maybe reconsider, but I like it better than the smartphone for viewing