Did you have supplemental brakes in your travel trailer? They all do for both added efficiency in stopping and in case of accidental break away from the towing vehicle. Why should I treat my towed any differently? You can justify whatever you want to; brakes or no brakes, up to you. You can interpret most laws any way you want to...until you wind up in court in which case you may find that the armchair legal minds on the internet may not have it exactly right. I, however, sleep much better knowing that my motor home's brakes aren't carrying any extra load, even if said load is within the maximum capacity. The brakes will last longer, run cooler and suffer less mechanical stress if the load is shared by the towed's brakes which are already there just waiting for a means of actuation. For what I spent on the motor home, the base plate, arms and light wiring, the brake actuator was a pittance. Should the unthinkable / impossible happen (you learn with age to never say never) and my towed breaks away, the safety cables will / should keep it attached, but, my supplemental braking unit will keep it out of my expensive diesel engine. The potential repair cost, even for the body work would pay for a supplemental braking unit many times over. As you can tell, I have a supplemental braking unit, an RVibrake 2, for the peace of mind and the 2 minutes it takes to put it on the floor and plug it in, it is priceless and for me a no brained purchase.
As I said, to each their own and you will probably do just fine without one until you don't, but, at that time it will be too late. For me the cost was easier to swallow than the gamble...the same reason I carry insurance on everything; to date, knock on wood, I've never filed a claim, but, you never know what the next few minutes may bring.