The point about learning Hapi is the clarity of its docs, the convenient learning curve, the strong backing and then adapt yourself to all frameworks.
Also, the best part is that there is a particular approach to things in Hapi. Compared to the slightly loose approach of Express where the developer can make decisions about how to approach the problem. Hapi guides decisions.
My approach in all these years has been to take up a framework that I can grasp fast and to not stop at it. Learn other frameworks after you're clear with one. Because you're likely to encounter more than ne frameworks in a job.
As a solution, choose a framework which has a good balance of plugins and which also, guides a solution, unless of course you want complete control, and the system will never be coded by anyone else. In a large team, a guided framework works.