You don't "need" a 3/4 ton but they sure are nice to have.
With 3/4 ton you get more brake, beefier frame, heavier duty gear and driveline components, etc. You also get some real sh*%ty gas mileage. I'm at 15 highway and 9 or so towing.
Nothing wrong with 1/2 tons at all, but the trap with max tow and uplevel payload packages is 95% of the time you end up at a price above the 3/4 ton when you add those packages, and at the end of the day its still a 1/2 ton truck. The only way you don't end up that way is if you catch some sort of sales incentive.
In the case of GM, I priced out the GM 1500 with all the towing enhancements and was close to 4K above my best price on the gas 2500HD. With the 1500 you get the 6.2 aluminum block Ecotec and with the 2500HD you get the Vortec 6.0 with cast iron block. GM considers the 6.2 a light duty engine and the 6.0 a heavy duty engine which is why they still plug them into the HD. Take a 1/2 ton, any brand, with the max towing and payload enhancements, and park it beside its 3/4 ton brother. Crawl under and take a good look. Huge differences.
I see lots of overloaded 1/2 tons coming into campgrounds towing 6K range GVWR trailers. Its not the trailer, its the 6 people, 3 coolers full of beer and ice, face-cord of wood, 6 bikes, 3 kayaks, two easy ups, Kenmore gas grill, and other gear that overloads them. Most of the towing public does not live and breath this stuff, or bother looking into any of it. They just hook up and go. Max payload package????? What is that?????