It’s in the shape of a full ham, still on the bone (so looks good set on the table), but it’s also pre-sliced. So if you’re feeding a crowd, you don’t have to do the work of slicing it (and the slices are more consistent than you can easily do yourself).
One thing I haven’t seen mentioned here is that people may be stocking up on Easter supplies. Since Easter moves around, there’s probably a year-to-year change like this every year.