If I'm being candid, what bugs me about this kind of marketing is that I work for a Silicon Valley company which spends a lot of hot air on "doing what's right"

If I'm being candid, what bugs me about this kind of marketing is that I work for a Silicon Valley company which spends a lot of hot air on "doing what's right"—and I want it to be true. So, for {altruistic, self-interested} reasons, I want to push back on the dilution of "doing good by doing well." To directly answer your questions on Robinhood, though: I believe (with low confidence) that the big innovation is gamification. That's it. And I have trouble feeling like that's beneficial. If Robinhood had gamified saving for retirement in a boring 3-fund portfolio with zero commission trades, I don't think we'd be having this conversation. But PFOF on once-a-month 401k inputs wouldn't be very good for their investors.