Most areas don't have 4G yet, so using the SGS3 as a hotspot gives you the glorious 3G as a repeater/hotspot. I, for one, have USED portable hotspot on my Optimus S when it was rooted, back when my daughter was in NICU at a big hospital, and the WIFI they gave patients access to was SO SLOW...I used my phone to surf the web instead of using the hospital's wifi..
Now, with that experience, I have to ask..who in the hell would want to really "STAY" on 3G when it sucks at speed like it does? It's not like we're going from 6meg DSL to 45meg fiber connections...the repeated signal of my optimus was sloppy with horrible ping times...
And the biggest factor....I'm already paying for data once. WHY pay for the same thing twice?
I guess I'd see it differently if I used hotspot as my primary means of surfing the net..but I have 6meg DSL at home and that's my connection. Plus I have an Airave (2nd generation, NOT the Samsung version) which DOES do 3G...
Now here's another thing I've wondered. I'm paying for my DSL connection. It's MY DSL. Sprint's Airave connects to that DSL to give me service via my Airave..but uses GPS and broadcasts a signal to my phones.. Since I had a problem with my service not working, Sprint waived the charge, monthly, for using the Airave...but other people sometimes get charged for using the airave monthly (like $4.99)...
They pay for their DSL connection, then they have to pay for the data and minutes that the SAME DSL connection provides and in-turn also powers the signal to their phone...so they are being charged by the DSL company to have internet, then being charged by Sprint to re-use that same internet (DSL) connection as data/voice on the box Sprint provides.
I guess I look at things a bit on the literal side..but I'm already paying for data on my cell phone bill once...just because I want that data to be used in another way...I'm still using the same amount (whether I'm using my phone to surf or my laptop to surf..or my tablet to surf.)....why does Sprint/Vzw/ATT/Tmo need to make additional money because you choose to use the data you've already bought in a different manner. They aren't charging you for using it as a hotspot, they are charging you for HOW you use that data (or with what devices I should say).