I use my UDS for smoking and have a large grill. My 26.75 Weber is perfect for the extra dish that I never seem to have enough room/attention for. For example, indirect heat grilled corn or chicken while I'm spending time with steaks or burgers, etc. on the other grill.
Baked beans, cornbread, etc. I used to try to do it all on one grill, but having the Weber gives me an extra tool, "on the side."
As others have said here, it is also a good smoker, as well.
"What are all these charges?" "Just things that we need for the house, dear."