"but I admit I still don't get what problem is this a solution to."
As mentioned, this is applicable to areas of restrictive gun ownership OR traveling hunters needing 2 significantly different calibers on the same "numbered action" to meet import regulations.
A true "switch barrel" should not require barrel/action vises, barrel nut wrenches, bench vises, pipe wrenches, or such tools. Often only a small torque wrench or maybe even just a T-handle hex/torx wrench is required.