It's a matter of safety. An inflatable is more stable, carries more load, can be boarded easily from the water, is stowable, doesn't do damage to other boats banging against them and is capable of more speed safely through rough water when matched with a good engine. It can also be easily used as a bow thruster for the big boat in an emergency.

A hard dingy is of course more traditional, prettier and has the ability to sail with the right setup. It also generally rows better but safety should always take precident.

An inflatable is just a safer boat.

Someone tell me I'm wrong.