Lightroom should catalog psb files, just as it does psd files. I have many psb files that are not over the 65,000 pixels per side or 512 megapixel limits, but are larger than the 4GB limit on psd files, and it would be nice to see them in Lightroom.
Updates to Lightroom Classic, were released yesterday and contain initial support for PSB files. Please install the appropriate update. You can read more about the updates here.
Note: Lightroom pixel-dimension maximums (65,000 Pixels long edge or 512 MP - whichever comes first) continue to be a limitation but the team is looking into expanding this range in a future enhancement for the PSB file support.