I skimmed this article, but I'll revisit it later because MPU protections have always intrigued me, in terms of being a much smaller subset of the protections afforded by an MMU. That said, for work projects, I've only ever been able to make use of MPU regions for coarse-grain protection (eg prevent the DMA-dedicated regions from being accessible by everything) and not for per-task protection. So I'm always interested in ways that more isolation can be applied, precisely because it keeps code honest, which isn't a bad thing. It's no different than having software asserts.