My parents use the happy hooker and love it. It does work very well. I agree though that a full turn around the mooring is preferable, but you could do that manually after using the happy hooker to get the initial setup.
Of course I've now found SEVERAL Washington state park buoys washed ashore, or have been dragged way out of position. I also have one friend that did 20K worth of damage, last summer, when he drug a Washingotn state park buoy aground, so I pretty much never use them anymore. I just carry my own mooring in the form of a 66# Bruce and 300' of 3/8 chain.