the only time that i would consider parboilng chicken (whole or parts) is when i have an awful lot to produce quickly for a large crowd, and/or if my marinade or grilling sauce has a lot if sugar in it and i don't have a lot of control over the heat. or when you'd rather be having fun rather than standing over a grill for a half hour or more.
to explain the latter, we often go to a lake with a public beach in the northwestern mountains of joisey during the summer that allows grilling in a restricted areas just of the lake. sometimes, we bring the smokey joe and a small bag of briquettes to make dinner, along with some salads. i've found i'd rather start the chimney, then jump in the lake, come back and pour the hot coals into the smokey joe, get it set up, put the parboiled chicken on, jump in the lake, come back and turn it, jump in the lake, come back and brush with sweet/spicy bbq sauce, then make a big sad face because i have to stand by the grill for a few minutes while i turn and brush the chicken a few morw times while setting up the salads and drinks on the picanic table.
after eating, guess where i jump when someone else cleans up?
the ice cream truck, silly.
ok, but outside of time constraints, heat control, and sugary sauces, parboiling is kinda ok but you're losing some flavour in exchange for convenience, limited grilling apparatus, or burning sugar.
in nomine patri, et fili, et spiritus sancti.
beidh ar la linn.
wisdom is often in short supply within ones' ego.