Well, we could run into problems that would require such mercantile solutions. If people have non-combat specialties I'll definitely be more likely to include situations that need them. They could also just provide party utility, such as better item discovery or use of one's surroundings, or allowing them to carry and use greater and more varied quantities of items.

If you aren't sure about a direction to take your character though, and feel like you'd be depending on me in order to get it over, you could go a different way. Ideally we should play characters whose intricacies come to us naturally.