This comparison doesn't make a whole lot of sense to me. It's like saying "when I need a dessert, I prefer pie to gelato". I mean, yes, they're both dessert, but they're not the same category of thing.

Debian is great, and it's somewhat famous for the wide varieties of architectures it runs on. But fundamentally, it's an OS meant for use on systems that look a lot more like a computer than an embedded device. It's true, there's a good amount of overlap these days -- the most common OS for Raspberry Pi's is a Debian derivative, Raspbian -- but if you were building an IP camera, it's hardly the first thing I'd recommend.

Yocto, on the other hand, isn't really a distribution of Linux as much as it is a pile of code that lets you craft your own distribution. In a way, it shares some attributes with Gentoo here, though much more narrowly focused. Yocto is meant to produce images that get "flashed", even if not literally to EEPROM; it has integrations with tools like mender, that allow A/B/x style failover on updates. You'd expect things made with Yocto to be upgraded in a single block -- OS, code, all of it -- because it's all meant to run together. Updating a single package isn't really how Yocto is meant to work.

All in all, I mean... yes, I agree with the fundamental point: in most circumstances, when working on low-resource embedded devices, you're probably going to want something more like Yocto than like Debian, but, also, it's a very strange comparison to make.