So, a common question we get about the random collectibles in the adventure mode (tires, toy pigs, etc) is what their purpose is. A lot of people expect to be able to spend them in some fashion or other, and we play off that expectation. If you play through the adventure and watch all the cutscenes, the "purpose" of the collectibles should become pretty clear... namely that they have no purpose.
So why have them at all, then? Well, it's partly a joke, and partly veiled commentary on my part.
I really am not a fan of achievements or of other extrinsic rewards in video games in general. My feeling is that if you have to give someone a prize for playing your game, your game must not be all that fun. However, conversely, there are some players who are so into the achievements and similar that they really want it in any game, and don't play games as much if the game doesn't have them. So we have always had achievements in our games, because of not wanting to alienate them. And I AM a fan of special challenges, which often are paired with achievements, which is a different sort of thing. That adds to replay value and is a worthwhile thing in my opinion.
And really, I'm not dead-set opposed to achievements, really, I do enjoy them in some games. I'm just opposed to the OCD-like way in which some players fixate on them. I guess that's an individual's right, but it doesn't seem healthy to me. In the story, the characters often comment on how you're picking up and hoarding a lot of useless stuff. And Socrates in particular has a past of being an extreme hoarder.
Mostly the fact that the collectibles are (surprisingly) useless is just meant to be funny, but it's also a bit of a jab at a lot of other casual games that give useless rewards that aren't
put in the game ironically. Preying on the effectiveness of that Pavlov's Dog effect seems morally dubious to me.
A lot of this talk about "extrinsic rewards" and a "subtle commentary" probably sounds pretty pretentious. That bugs me about the "artist's statements" with a lot of indie games; if you have to explain it for it to be significant, that's fairly pretentious. My explanation here is mainly just for people who skip the story or who didn't play all that far through it yet and are deathly curious about it. This commentary isn't intended to be elitist or pretentious, but rather just a simple observation that these sort of collectibles are often trash at best, and feeding an unhealthy hoarding habit at worst.
And, if you go through the actual story rather than reading this first, we think it's pretty funny to realize that you've been lugging around all these spare tires for nothing.