heres the usual scenario:
take a family with 2 small kids. You create on family contact with 4 birthdays, 1 anniversary, maybe 2 or three other dates belonging to them.
Or a company with two or more employees you know there. I dont create two or more contacts for this, but combine them in one. So if I get some birthdays I want to list them as user defined birthdays: employee1 (support), employee2 (finance) etc.
I already knew the birthday adapter but this doesnt help if I cant create more than one for a contact ;-). But if it works with davdroid contact thats fine.