The design presentation is the sale, and most builders under-prepare it
Customers cannot picture a pool in their own yard, and the meeting where they finally can is the one that closes.
A homeowner looking at a flat patch of grass has no idea what will fit, how it will sit against the house, where the sun will be at four in the afternoon, or what the space will feel like. Everything before the design meeting is abstract.
Three dimensional renderings of their actual yard, with their house in the frame, do something no gallery can. The customer stops evaluating a builder and starts wanting a specific thing.
The preparation is what separates builders here. A rendering built from a real site visit, real measurements and the actual constraints of the property is persuasive. A generic shape dropped onto a photograph is not, and customers can tell.
It is worth deciding what happens in that meeting deliberately: what is shown, in what order, what gets decided on the day, and what the customer leaves holding. Most builders run it by instinct and get inconsistent results.
Charging for design is a legitimate model and it changes the conversion conversation completely. A paid design qualifies the buyer and pays for the work, at the cost of fewer meetings. Either approach works. Drifting between them does not.