Not when your trailer and caravan use an Anderson plug, like most other cars in Australia. Having all three gives you flexibility. If you get stuck remotely a third party may need to tow your trailer/caravan out, and they will not have a NATO plug.NATO because it screws shut has a higher amp rating and is robust possibly use it for jump starting winching etc
I travel alone in very remote parts of Australia, so I need to plan with redundancy and flexibility in mind. I am not saying others have to follow suit, but it is another option.