If the results are instantly deposited to my bank with no further action required I'll take the $2. The take-away I see is people don't have unlimited time and effort for the noise that gets offloaded onto plebs.
I'm not getting out of bed for a $5 gift card that only redeems through some phone app and/or requires creating an account.
Myself, I wouldn't bother with a $50 gift card that only redeems through some phone app and/or requires creating an account. I'd surely cave for $500. Or the five-dollar bill that has "no further action required" built right in.
This isn't really news, price tags have long since exploited mail-in rebates and other tediums. The expected n% that actually use it will have been well known from many such cases, people can't be assed and those that do become data.
I suppose this is what they mean by "induced value theory"? At a glance it seems to mention individualistic preference a lot, but the fact is a $50 bill is more valuable than a $50 gift card, there are places online where people try to barter them around p2p (at a loss, of course) there are places that offer cross-redeem services so you can pay service X with giftcard Y (at a loss, of course)
It wouldn't surprise me if other experiments resorted to EGC because it ends up costing them less than giving participants cash. Other events, giveaways, lotteries, so on.