Dennis, there are tons of BBQ contests in my neck of the woods and I see lots of these containers in use to "cooler" cooked meats. I assume these must be well insulated and would hold heat a long time if left unopened.
There is an added benefit to "coolering" besides just holding at a foodsafe temp (+140). Once removed (I'm refering to mostly butts and briskets here) from the cooker, the residual heat will continue to break down the connective tissues in the meat without the risk of drying that continued cooking and raising the internal temp of the meat would present. Most teams plan their timing to have at least 2 and usually 3 hours of "cooler time" to take advantage of this. Most serious competitors will wrap their butts and briskets in several layers of plastic wrap to help keep the juices in the meat before foiling. Obviously this makes the bark squishy but is fair trade for an additionally moist and tender finished product.
For home cookin' I take what the cook brings me and if a brisket gets done early, it gets some cooler time. I actually prefer it straight off the pit but big cuts like butts and briskets are done when they get done, not necessarily when I planned.
Since I don't already have the stainless pans, the containers are a little pricey for my budget so I use an Igloo 5 Day Ice cooler. The bottom of my old meat cooler warped from heat badly, so when I bought the igloo I scrounged some 1" foam insulating board and made an extra bottom to protect the cooler. I also cut another piece to go on top of the meat so I don't need blankets or towels. Keeping pork fat off the linens also helps ensure domestic tranquility