I think the power of #WIIFY really shines in its double role to promote cooperation (the #FLOSS example) and guard against exploitation (as seen for the social networks based on open standards vs corporate silos).

So #WIIFM kills #FLOSS twice: once (on the author side) by removing an incentive to sharing one's work, and the second time (on the user side) by giving a sense of entitlement for something one is _not_, actually, owed.
The #WIIFY mindset, OTOH, promotes both #FLOSS production (as adopted by the author) and responsible usage (as adopted by the user).

Now that #FLOSS is taken for granted, and users don't ask anymore #WIIFY of the developers, but only care about their own #WIIFM, #FLOSS development has become a stressful, negative experience for the authors of projects that reach any amount of success and notoriety, as they get flooded by entitled demands for assistance and feature requests, with no expectation of compensation for the work they would have to put in beyond their own personal interest.

Now that #FLOSS is taken for granted, and users don't ask anymore #WIIFY of the developers, but only care about their own #WIIFM, #FLOSS development has gotten a stressful, negative experience for the authors of projects that reach any amount of success and notoriety, as they get flooded by entitled demand for assistance and feature requests, with no expectation of compensation for the work they would have to put in beyond their own personal interest.

Now that #FLOSS is taken from granted, and users don't ask anymore #WIIFY of the developers, but only care about their own #WIIFM, #FLOSS development has gotten a stressful, negative experience for the authors of projects that reach any amount of success and notoriety, as they get flooded by entitled demand for assistance and feature requests, with no expectation of compensation for the work they would have to put in beyond their own personal interest.

#cuiProdest is still useful for more roundabout proposals. For example, post.news used a #pyramidScheme for onboarding to pump up the numbers when it had barely just launched and create noise to divert from the attention #Mastodon and the #Fediverse were getting on the first #TwitterExodus. People were sharing their referrals to invite others to join post.news hoping to move faster in the queue (#WIIFY), but this was all to the benefit of the post.news' owners.

#cuiProdest is still useful for more roundabout proposals. For example, post.news used a #pyramidScheme for onboarding to pump up the numbers when it had barely just launched and create noise to divert from the attention #Mastodon and the #Fediverse were getting on the first #TwitterExodus. People were sharing their referrals to invite others to join post.news hoping to move faster in the queue (#WIIFY), but this was all to the post.news benefit.

But this isn't just a rehashing of the good old Latin phrase «cui prodest?» (or «cui bono?» as some of you may know it). This isn't just a matter of asking who benefits from the proposal, because it will _always_ be sold to you as something you can or will benefit from, and generally as something that both (or all) parties will benefit from. #cuiProdest, #cuiBono are always good questions to ask, but #WIIFY is really the game changer.

In fact, even the #WIIFM mindset being mostly contrasted to some assumed sense of self-sacrifice for the greater good of everybody (else) is essentially a propaganda strategy to empower WIIFM. And yes, this is done on purpose to distract from the fact that overcoming WIIFM doesn't mean self-sacrifice, but rather the inquisitive question: «what's in it for you?» (#WIIFY)