You had me at proprietary. But seriously, I use FOSS. I'll tolerate proprietary software if I have absolutely no other choice. There's absolutely no reason for me to put up with this bullshit. While it's a long way from the kind of shitfuckery Microsoft is so fond of, it's still completely unnecessary.
Proprietary doesn't bother me at least not how snap is currently implemented
I don't recall noticing a size difference between snaps and flatpaks
I've found snaps as fast as flatpaks, but I know snaps has issues before I started using them
Honestly, if you're satisfied, there's not really a compelling reason to switch. Keep using snaps if that's what works for you. But I would like to remark that we should preferably support open solutions to proprietary ones. That's not saying that we should never use proprietary software, but just something to keep in mind.
Me reacting to analogies with "Did you know these two things are not completely identical?", completely unburdened by the knowledge that I'm supposed to explain how the differences invalidate the comparison.
I'd argue it's pretty stupid to use FOSS but then depend on a proprietary server that only one for-profit company is allowed to run to deliver all that software, trusting them to just never do wrong or leave you high and dry. I'd also argue it fits the analogy perfectly, because the analogy was about saying "I haven't had a problem yet" in response to being shown the potential problems of the action.
But the problem with snaps is an opinion. If Canonical goes bonkers I'll just go use something else. Until then I don't have any issues with them using proprietary software within their own ecosystem.
It's not an opinion that proprietary for-profit software will betray you, it is an inevitability. It has happened every single time. If it was FOSS, we could salvage it. It's proprietary, so we can't. When it fails it must simply be abandoned. I just hope you learn the right lesson when this happens.
WinRAR will either die, or be sold and squeezed by its new owners. Nobody lives forever and no asset goes unflipped in this market. You can say you won't update, but that just leaves you vulnerable.