For the hop heads. You'll get a puckering bitterness from the Nugget hops with plenty of flavor and aroma from the Goldings and Fuggles. Very hoppy, very British.
By itself, Scotch Ale has a wonderful reputation for being malty sweet tamed with a warm alcohol note. Adding a little smoked malt compliments the sweetness like a fine Single Malt Scotch. Barley malt grows well in Scotland but hops were almost unknown, so this style features the maltiness and downplays bitterness.