I have had both situations (no compressor and with compressor). If you can pay the extra for the compressor, here are my advantages having one:
1. No need to carry a pump
2. The simplicity of having a compressor means you can change air pressure on the fly
3. I like going down the road and when conditions warrant it, I can add or release air on the fly to adjust my ride while I'm driving.
4. When loading and unloading the camper, I have complete control over my bed height at the flip of a switch.
5. Some people have figured out how to tap into the compressor to use it for other needs; (e.g. Blowing up inflatable kayaks, balls, etc.)
6. If heavy winds come up while driving, you can add air to one side to reduce lean
7. Sometimes, I only need a bit of air to level the camper. Nice to do that inside the camper while watching my level.
