I don't follow the logic on this.
I have no interest in this app, because I have gotten started and created a solid investment plan already, and don't need to try and save pennies on the side. Buuuuut... really, you don't follow the logic
at all? You don't see the value to someone who hasn't yet learned to save and invest, or to someone who finds it difficult to transfer $200 a month into their savings but really just needs this kick in the pants to get going?
You brought up the best reason in your post. It's a psychological thing. Which is what nearly all investment advice is about. For example, if the point of investing while in the accumulation phase is total return, then everyone should be 100% stocks (or possibly 90/10 or 80/20). Yet many people are 70/30 or 60/40. Why is that? Because of risk aversion. There is no logic there, it's all about emotions. People can be emotional when they "lose" money, so they invest more in bonds so that when equity markets drop they feel like they aren't losing as much money.
That's the idea behind this app. It's not for us, it's for those who haven't yet made the plunge into saving/investing.