I rooted my phone only so that I can use a foreign SIM when I travel to Europe this summer - which I may or may not end up doing. None of the reasons listed in the "9 reasons" blog is that compelling to me, personally - and you don't need to root in order to tether with FoxFi, which is great. I'll admit I feel more secure having backed up with Titanium Backup, though it takes a long time.
I think rooting and unlocking a phone are different. One of the people at my work has a Note 2 that is unlocked and not rooted. He is able to use a foreign SIM when he travels overseas. I use a Sprint phone, so I have to drag two phones with me when I travel. My Note 2 for Android and a unlocked Blackberry for calls and texts. I would verify that rooting allows you to use a SIM from a different company because I think you need to unlock the phone.