And if you call any software support company, they'll tell you to uninstall/reinstall the software if you're having problems. That doesn't mean it is a necessary step to get the problem solved. They're just going to have you perform basic troubleshooting measures to cover all bases. If you're calling Samsung for help on an OS problem, that is a carrier issue, so of course they're going to tell you to reset the device. That's the only thing they can suggest, they're not the carrier.
On the support site for my carrier, nowhere on the update instructions does it indicate that a reset is required or recommended as part of the process.
It is only recommended if you're having problems after the update.
But hey, if it makes you feel better to reset your device after an upgrade, nobody is telling you not to. I won't fault you for doing it, if that is what you want to do.
I'm simply saying, if your device is working just fine after the update, there is no need to reset it.