You do this after every smoke?
No. It's a little too much for me. But I do it about once every 2 weeks or once a week if I'm diligent, between hot/warm water flushes.
It really does work well.
The water is fine, but after the soap and some drying time, which I'm sure you know is minimal, it is like having a brand new pipe but the benefit of a little cake built up. Any trace of oils or contaminates are gone. A little more so than the water alone.
I keep the cake in my pipes well trimmed back. Almost to the wood, I suspect, but still there. Either way, the soap and shank brush doesn't seem to remove the cake and it dries rock hard.
I wouldn't bullshit anyone here. I really do use this on pipes that I consider to be somewhat valuable. I think the biggest impact is on my bamboo shanked stems because they seem to collect the most oil, despite water flushes. I have two Eltangs with bamboo and a Dunhill with bamboo. I think it even helps to restore the bamboo. Obviously, I can't confirm that, but I just suspect that bamboo likes to be moistened once in awhile.
But even wood shanks, after a hot water flush, turn out a lot (A LOT) of brown crud with a shank brush and soap. Just don't scour the finish with a dish pad and they're in the same great shape as hot water alone.
No joke.
No weird swelling or otherwise bad effect.
An aside; I think the rejection of water to a pipe is pretty funny. I haven't read about a bad experience yet. I have salad bowls and other food bowls made of wood that get soaped down and oiled after use. I've had them for decades. Weird that they still look great!
Actually, that's how soap and pipes came together for me. I had just washed a salad bowl and had a pipe I was going to flush with hot water. Then I thought, well, what is the magical difference between this beautiful rosewood bowl and my briar? Couldn't come up with a logical reason and I didn't look back.
And yes, my pipes are in great condition. Almost half of my pipe smoking pleasure is from looking at well made, shiny pipes. They're in "as new" condition.