There is a lot of growth in Caledonia and I believe it's intended to serve the airport and industrial lands in Hamilton around the airport which will be getting built soon - but generally, I agree that I'm surprised to see it get funding. Especially since there are so many much more pressing projects around, even in the Hamilton region.
PIC 1 had it be a full, 100km/h freeway, so there will be a full interchange at Book Rd and the Airport, as well as a reconfiguration of the intersection with Upper James of some sort.