I own several aluminum trailers - mostly Featherlites, and use aluminum for many other projects
These are cargo type, but I made, or had made, cabinets and storage areas with aluminum.
Aluminum is great - light, strong, does not rot, no smells, etc., everything noted above, and more. But...
It has drawbacks too.
Cold/Heat - I equate an aluminum trailer to a thermometer or an aluminum beer can - If it's hot outside, it hot inside, cold out, cold in. Near 100% thermal transfer, and very difficult to provide a thermal break to stop the transfer.
Noise - Harmonics make aluminum louder than any other material. Installing sound deadener sheets helps, but still loud - Think race car. If this camper is open to drivers compartment, you will need effective sound control, or it will make for long noisy drives.
Stark look and dirty - The look of bare aluminum sheet has it's moments, but... It is also dirty, as it transfer gray/black to anything that comes in contact with it that moves or vibrates.
Great material, but, good planning and execution are needed to make it comfortable.
Good luck.