Thanks MJ!
I'm supposing that dutch roll is not a serious problem in a straight-winged aircraft designed for 120KTAS cruise at 5000' or so, and the only other reason I could come up with was the same as you did.
Seems odd for an air force basic trainer to have the coupling just to make it easier for the pilots to stay co-ordinated - I thought air force pilots were better than that...
Oktas