I too am not sure it is worth it either - unless the N7 was to replace your android phone. But that is not really practical either because of size.
Unfortunately, my phone's plan (Straighttalk) though "unlimited data plan" will cut you off if they suspect you are using tethering. That really limits the n7 away from wifi soures and is the only reason I was looking into it. But you are correct. Not worth it.
Incidentally, FWIW a week ago I bought my Nexus 7 16G WiFi at Staples for $199 which is better than Amazon.com's price of $232.85 for what I think is the same item. May be useful to someone.