So I had a '14 13"(? Might have been 15" but probably not) RMBP on the left with email and chat stuff, 24" main monitor in landscape and then another 24" monitor in portrait on the right. I think at some point I put a newer panel on the IBM mount. It was sweet.
Back then we still had desktop PCs at our actual desks so there was a KVM on the main monitor! What a time to be alive!
These days I do prefer a single monitor workflow if possible. It's just cleaner and move convenient.
Plus, if I take a working vacation somewhere it's a lot more practical to schlep around one 24" or 27" than an ultrawide.
Also, just as an ergonomic thing, I could angle in the two outer screens a bit while not having one of those icky curved screens.