Banjo's Insight - why does a grill have a dome, and when would I use it?

Better grills have domes.  But when do you use one?  It depends on what you are trying to do!

A grill, by itself, is a single point of high energy heat.  It will cook the bottom of a piece of food, subjecting the food to a blast of high heat.  Meanwhile, the top of the food is not being subjected to any heat energy, so it is not being cooked (OK, a little bit by hot gasses moving past the food as the heat move upwards).

By placing a dome onto our grill, we create an OVEN.  And when we are in oven mode, we are cooking food from all sides - by the heat source, which may be directly under the meat (but can also be on the other side away from the food - which would even more closely simulate an oven), as well as from the metal walls, lid, and air.  So with the dome on, we have an oven, and it cooks like an oven.

So when would you want to turn the grill into an oven by placing the dome onto it?  Primarily, when you have large pieces of meat that require a long time to cook, so you want to transfer the heat at a rate that will allow the heat to migrate through the entire piece of meat.

So when would I want to  use the grill as an oven when I've already got an excellent oven inside?  You would definitely want to use the outdoor oven when you are wanting to import any flavors from the heat source, such as from lump charcoal, wood chips, etc.  Also, if you are quick browning the outside of the meat, you would want to place the meat directly over a high heat source when you browned it, then transfer to the side of the grill not directly over the heat source, close the lid to create an oven, then allow sufficient time to allow the interior of the meat to come up in temperature.

By the way - a better way to cook steaks, but seems not to be understood, is to first cook the meat in oven mode until it is almost at the desired temperature, then move it directly over the fire to blast it with high heat for a short amount of time - not long enough to over cook the interior.