I'm positioned in the sweet spot when listening and usually keep being seated there for the duration of the session, and yet I went for a pair of speakers that have a wider sweet spot compared to my previous speakers, because of what it does to the sound in that more or less fixated position.
If one were to visually outline it, it relates to how the overall presentation is "shaped" in front of you, and with a wider and higher dispersive nature compared to the earlier scenario (that now also involves physically taller speakers) - yet controlled by 90 x 40° Constant Directivity horns - it makes for a more enveloping sphere or bubble of sound, and one in this case more coherent and smooth at that. While sitting centered in front of the speakers is still preferable the presentation doesn't fundamentally change even when moving to the left or right seat in the sofa, and it has a relieving and relaxing effect on the listener. To me at least this type of presentation is more reminiscent of a live music event, if that's your thing.
Certainly the dispersive nature of dual 15" woofers and a Constant Directivity horn per channel is narrower than smaller, direct radiating speakers, and yet makes for a full, enveloping and rather dense (akin to live music, to my ears) presentation. Maintaining a uniform dispersion pattern over the cross-over region is also very important in creating a homogenous bubble/sphere of presentation.
I suppose with a wider/higher sonic field of presentation as something that relates to a live presentation, it may link more innately to being an audiophile as someone who cares about mimicking such an event, and yet I feel omnidirectional speakers like MBL and others are too "wishy washy" to instill that sense of realism and presence akin to live music. YMMV.