Concept of showing the less appealing side of the project you're working on, showing where there's friction, roadblocks, where it's uncomfortable
Diametrically opposed to marketing which shows the polished, final product in the most flattering way possible
This makes for a more engaged audience
I suspect it's because people enjoy a narrative, opening, plot, complication, resolution. People want to see problems solved, it will give them a sense of accomplishment by proxy. They will invest their time
I think this concept applies to content like home renovation work: led in paint, asbestos in the wall... provided there's enough progress, people will follow along