>>My question is: Why not simply throw all the specialty grains, oats, and base malt in my nylon steeping bag and do the entire process in the brewpot itself, while maintaining a constant temperature on my stove. And then just pour sparging water over the bag while suspending it over the brewpot.
Many people, including me, do this.
Mash all the grains at say 150F for an hour, pull out the bag, let it drain, SCOOB*, and then boil. Makse for an easy and shorter drew day.
(SCOOB = Squeeze the Crap Out Of the Bag)
>> I'm sure this is a noob question but I'm just looking for some clarification on how the process differs from steeping in the brewpot.
Steeping doesn't result in mashing (i.e. no conversion of starch to sugar). Its solely to extract flavor, and maybe some sugar from the grains.
Steeping is done at a higher temperature, like 165.
>>Does the process shown in this video simply serve to give closer control over temperature regulation and better extraction from sparging?
Its a different process.
When you say Sparging, do you mean mashing out (at 168)?
The purpose of Mashing out is to denature the enzymes (make them stop working) to lock in the wort sugar profile.
It also is easier to extract sugar from the grains at a higher temperature