I imagine attaching files in-line is one of these things, but maybe there's other stuff you can't do without?
Yes, this is hoarding, but, as opposed to the physical kind, where it goes from some neatly displayed trinkets, to inaccessible rooms and biological hazards, computer files allow us almost infinite room, and almost infinite structure.
While it is probably not healthy to entertain the idea, I believe most hoarders, given sufficient physical space (infinite, really, is sufficient cannot be determined before they're dead and no longer amassing objects), their collections, their order, would look somewhat neater (although not any less pathological).
Whereas physical objects are a burden both in weight and volume, a few hundred terabytes of data does not take up significantly more room in the physical realm.. A file server, and its backup, is really all it takes..
So I don't think they're comparible.. At least, it depends, also, how it affects you, is it a source of stress and negativity, or simply a peace of mind, or a mad obsession..
I don't delete stuff, but I don't fuss over it either, it's not a big deal, once in a while, I move everything out of sight, it's a very small effort, and, so far, 30 years later, current me is grateful for past me for leaving those little breadcrumbs to spark my memories, and so, I will continue this tradition, in honor of future me.
Very lightweight bullet-points. That's it.
Be honest with yourself: other than the occasional search, when is the last time you referred to notes you took X years ago? And for the search-cases, how outdated was that information? Is the sequence of commands you painstakingly saved a decade ago for how to rebuild an array in megaraid really relevant anymore? Could you not have just, ya know, just googled it next time you needed it? Is your written-out explanation for how heat pumps work from that time you were re-doing your home heating system really useful.. when you can just have a conversation with Gemini about it now?
Less is more.