But what is a "natural connection point"? Unless you want to say Alaska Air has a hub in Anchorage, flying a straight line from Nome to Seattle would seem a "natural" routing -- unless, of course, there is a limit on stopovers if an "easier" routing is available!
I have little doubt that this is an extremely unusual use of BA miles - but a potentially good one!
BTW, one fly in the ointment might be getting to SEA from elsewhere in the lower 48 on Alaska Air. Their inventory looks very stingy for summer travel on their longer haul flights. It looks quite good for Alaska and West Coast segments.