From their IndieGogo campaign:
The ShiftCam Multi-Lens Case is a compact, integrated multi-lens iPhone case, now available for the iPhone 11 & 11 Pro, that switches lenses in fractions of a second — adding unparalleled versatility and quality to your iPhone 11 & 11 Pro cameras.
This case looks super bulky but I think it would be a great option for those occasions you plan to take lots of photos or go somewhere.
I am backer #83 on this and I intend to try the hell out of this once I get in a month or two. Until then. I will be drooling over the photos on their IndieGoGo.