There are a lot of problems that can be solved by an inflatable boat. The first is what to do when a person does not have a truck capable of hauling a boat. Really, a deflated boat of this sort can easily fit into a bag and into the back seat. Some effort is required to fold it and deflate it, but it really does solve a problem of taking a boat to a distant or remote location. There is no need of a trailer or the horsepower to carry a heavy load.
Another problem that a rigid inflatable solves is that it provides a solid craft that is lightweight and affordable. Not only does it cost far less than a fiberglass boat, often costing a fraction of the price tag, a fully inflated boat is often capable of housing an outboard motor and traveling at admirable speeds.