I always thought coercion was about talking. If you look big and scary, sure, why not add a boost die or two? But what happens when he meets another tough guy or girl who is even bigger and stronger?
And in many situations it should or at least could just be roleplayed and acted out if that makes more sense. You don`t always have to rely on the mechanics in a rolplaying game, story and rp comes first and thrumps the mechanics.