When selling use all available resources. If the company you work for has specialists or subject matter experts in a specific area or over a specific product make sure that you use them.
When using a subject matter expert or specialist on a specific product or service that you offer, both you and your company come across as a trusted advisor and an expert in your field.
Using resources on sales calls helps when making a recommendation based on the customer's specific needs because the knowledge from the trusted advisor or specialist helps add value.
Specialists or subject matter experts help you gain knowledge that you didn't have before and also reinforce that you don't know everything. It's one more way to model the way by looking for help and understanding and showing that you don't know everything.