I’ll give you the reasons I bought a small RV over a trailer. There are always trade offs!
1. You can boondock much more discretely. I can move quietly from the driver seat into the sleeping area without letting the neighborhood know anyone is there at all. Also safer in that if someone is bothering me, I can also just drive away.
2. Much faster to setup. I usually just hop out of my rv, connect the power cord and back in. Press a button for leveling out. When you have a trailer and you need to go somewhere, it probably involves disconnecting the hitch which is a ton of work. It’s possible to leave it connected but the length of both the trailer and car is usually too long for a campsite
3. Slightly related to that last one but length. My RV is 24 feet, I can just pull straight into most driveways, press a button and I’m setup. Not a fan of backing trailers into steep or across uneven driveways.
4. Incredibly easy to drive. As other people are discussing letting folks overtake you, it just wasn’t as necessary because you can drive a short rv like a car. Miss a gas station? Just hit that uturn at the signal and go back. Good luck with a trailer or even more fun in a 5th wheel
5. Cross wind. I haven’t driven much with a trailer but in the desert, the cross winds were sorta scary while driving an RV. I have to imagine this is worse with a trailer.
6. Having that back living space easy to reach. Thirsty on that 6 hour drive? Just send a passenger back to the fridge to grab a cold drink or food from the pantry
7. Storage. This can go two ways but I only have a driveway for two cars. My RV fits in one spot. If I had a trailer, I would have to park the truck separately which wouldn’t leave room for another car off the street
8. Battery recharging. When the RV is running, the deep cycle batteries charge. I can let the car idle instead of running the connected generator. There is also a button you can hold down and it uses the deep cycle batteries start the car engine in case the car battery dies. The whole system is integrated so you theoretically can’t have a dead battery on both the engine portion or the rear living space portion
9. Ac, I have had issues with my rear AC, I can start the car and run the AC from the front vents to keep the back area livable