This thread has certainly some strongly held and sometimes conflicting beliefs, like briar breathing or needing to be smoked to become dry, etc.
Most of what I smoke are estate Brit wood, and the top makers thoroughly seasoned their wood before finishing. So do artisan makers like Talbert. So it's news to me that there are pipes being fashioned with green wood. Seems like a terrible idea, one that makes for lousy joinery. Nor do I find it easy to accept the notion that smoking a pipe dries it, as smoking a pipe introduces moisture into the pipe. How introducing moisture into a pipe helps dry it out is a topic I'd like to hear explained.
As for breathing, I'm reminded of the images of pipe bowls that have been bisected to reveal their cross sections. Despite years of use and hundreds of bowls smoked, they revealed little seepage of tar, or other discoloration, into the wood. The worst damage seems to be charring and cracking from clueless smokers who smoke too hot. So I'm not too convinced about breathing, either, any more than with any other wood product.
Briar isn't some alien life form. It's wood, like any other wood. It expands and contracts from changes in temperature and humidity like any other wood. Its superior fire resistance is due to the presence of silicates in the wood, not any magic.
Having a thin cake won't hurt and whether it's the thickness of a dime, or a nickel, or less, it's still a thin coat. Cake doesn't help at all at the bottom where it doesn't build up, and where burnout from "smoking it to the bottom of the bowl" and getting every last shred of leaf burnt, super heats the bowl. Making a goal of "smoking it to the bottom of the bowl" is a dumb ass practice. More dumb ass when you consider that the flavor comes primarily from the tobacco surrounding the burning leaf, not from the burning leaf itself.
Whatever interaction between smoker and pipe is taking place, it would appear to be happening primarily at a very thin depth of the inner surface, not including heat dispersion through the wood. Keeping that thin depth in good condition would seem to be the critical factor in keeping a pipe a source of enjoyment.