You wouldn't build a house without a blueprint
When you’re building a house, you hire an architect who does the complex feasibility studies, the intricate design work and makes sure the project can be delivered for a sensible budget. Then you give those blueprints to a builder who does the construction.
When you’re building complex and functional software, it makes sense to build a prototype for exactly the same reasons. Once built, it will give you the clarity and answers you need. What’s a must-have? What’s a nice-to-have? Does the concept work? Do the clients like it? Is it worth the money?
Maybe, after the process is complete, it needs more work. Maybe we need to hand the blueprint over to an agency to build a more sophisticated product (for example, I don’t build mobile apps). Or maybe it does everything you need, with no fuss, no complex options, in a way that keeps your clients incredibly happy.