A portable gas barbecue is the compromise between a single burner and a charcoal fire. You get a wide cooking surface and something close to instant heat, plus a control knob, which charcoal cannot offer at any price. It is ready in about five minutes rather than thirty, and it stops when you turn it off rather than when it decides to.
The trade is weight and fuel. You are carrying gas, and a barbecue burns through it considerably faster than a simmering stove does. For a weekend it is a non-issue. For two weeks off grid it is a supply problem worth doing arithmetic on before you go.
For the cooking on this site, the honest comparison is that a gas barbecue does very little that a single burner cannot, unless you want to cook for more than about four people or you want a hot flat surface. If you are choosing one thing to carry, the burner is more useful more often.
Gas produces carbon monoxide too. Burning propane or butane in an enclosed space is dangerous for the same reason charcoal is, and “it has a flame I can see” is not a safeguard: carbon monoxide.