Shit rolls downhill the same way water does. It’s easier that way. Else you have to pump it uphill and that’s time-consuming and more expensive.
The reason the bottom-up, user-centered design is not attractive is simple. It’s slow and expensive, and the problem you thought you were solving might not turn out not to be the problem at all. Iteration, testing, and rapid validation of methods are not for everyone.
The choice appears simple enough. Go with the flow or let friction inform you.
Bottoms up!