Maybe replace with C. kousa.

Talk to your local people about how prevalent anthracnose is - arborists, county extension agent, university, forestry people, etc., etc.. Not living in the PNW, I only know that it is common there, both in the native dogwood and in C. florida. There may be growing/cultural practices that will keep it at bay - air circulation, amount of sun, etc. I can understand not wanting to spray every year, but many people do, both for ornamental trees and orchardists for fruit trees. I guess it comes down to what YOU are willing to do, and only you can decide.