my personal definition of it is this: a non-essential (or classified essential, but over-the-top, exotic, extravagant, and/or inefficient for the purposes of fulfilling human need) commodity that has an unfortunate capital-T Tendency (as in, the TPRF in which it applies without fail) of being invoked in political discussions, almost always making said discussions objectively worse.
A sub-classification of treats, which I wish more people would directly invoke instead of using the broader term since it's funnier to me, is the 'adventures': escapist, less-than-nuanced fantasies that are, without fail, invoked by people to explain complex political issues.
Any additions? Disagreements? we must synthesize this before it becomes the new tankie in watered-down 'thing i dislike' applicability.
This is how I see it, too. Good comment. IMO "treats" aren't funko pops or marvel movies or vidya games. It's the fact that you can buy a bookshelf at Target for $10 because you're not paying for the exploitation of the workers or the environment.