A couple of disadvantages to using the S7:
The mobile hotspot sucks the battery down pretty fast, so you might find your phone dead when you need it. Obviously this can be prevented with a little forethought. If you keep the phone charging while using the mobile hotspot app, the charger will more than keep up with the depletion rate. Otherwise, just keep an eye on it.
I don't think you can make/receive calls while using the mobile hotspot. This could be a problem if you are expecting an urgent call.
Otherwise, it's simpler to use the phone app than haul around another device.