arlen michael holder wrote

I keep hearing people suggest "baking soda", which is, as you know, simply
sodium bicarbonate which you can get a five-pound bag of for about five
bucks or so at Costco.

My question is more toward figuring out WHY I see baking soda mentioned
as a panacea for almost everything from baby rash to automotive leak
repair.

Even sillier than you usually manage, and that’s saying something.

I've had my five pound bag for YEARs, where
it will likely last me the rest of my natural life.

All the evidence suggests that you have a very unnatural 'life'

What can you DO with it if you don't own a pool?

Sure, you can use it in cooking, but this question is about home repair.

Use it to neutralise acids.

On another thread, someone said he was going to try "baking soda" to clean
a toilet bowl, where I have to ask what on earth is baking soda going to
do?

It’s a viable abrasive that is easy to get rid of once you have used it for
that.

OK. SO it's a bit abrasive, but if that's all you want out of it, sugar
would do as well, wouldn't it?

Nope, not as abrasive and baking soda is easier get rid of once you are
finished abrading.

What baking soda is, is an alkaline (that is, not acid)
bicarbonate, that is, it's "hard water" in dry form (sort of).

Utterly mangled all over again.

Other than the abrasive quality (which has nothing to
do with the chemical action), what USEFUL things around
the home (other than cooking) can baking soda do?

Anywhere you need a milder safe alkali.

My question is more toward figuring out WHY I see baking soda mentioned
as a panacea for almost everything from baby rash to automotive leak
repair.

It isnt.