I use a charcoal basket in a lot of my cooks with the Weber Jumbo Joe because it just makes it easier to contain the fire to a discrete single zone. I started using a charcoal basket since I already had the two that came with my 22.5 inch Weber kettle.
I am not going to try to convince you that this is a “must have” item. I doubt I would have bought them just for use with my Jumbo. You can do almost as well by simply banking the charcoal to one side of the grill. One possible advantage of using the charcoal basket is that it forces you to uses the same amount of charcoal each time so you will be much more consistent in your cooks.
The charcoal baskets can usually be found at Home Depot for around $15. They come as a pair; I am not sure you would even need the second one when cooking on the Jumbo. But hey, if you need a reason to head down to Home Depot and mess around with the grilling equipment this is as good a reason as any. You can also buy these through Amazon
The charcoal basket keeps things neat.
Be sure to check out some other Weber Jumbo Joe Upgrades!