I have 4.56 gears in my 4.0/3 speed auto. I have 33" tires in winter and 35" in summer.
I definitely prefer the get up and go I feel when I have the 33" tires on.
If I could go back in time, knowing this, I may have gone 4.88.
(I was trying to balance having 33"/35" and concerned about highway speeds.
But now I want my next set of winter tires to be 35"...)
With that in mind, and in addition to all the math previous posters provided, I think deeper gears are also more often recommended because even though a poster says "I'm only go up to 3X" tires"...more often then not, there comes a time when that poster wants to go bigger.
There is just a lot of experience and wisdom given with some of these posters - and they're trying to impart their knowledge, as they've seen these same questions cycle around all the time.
Just like you rarely hear a poster say "I'm so glad I want with the 2.4L instead of the 4.0L", you'll rarely see people complain that they went too deep with their gearing. I mean, it can happen, especially if they actually do go down in tire size - which does happen - but I think happens much less than people wishing they leaned on the deeper side of gearing. Once you feel that "oomph" when you press the gas pedal...it's kinda nice.