You stop overloading customers who are already close to deciding
Sending the whole catalog used to feel like helping, but in practice it left the customer alone to compare a pile of similar options. With one main pick and at most two alternatives per reply, they get less information at once and decide more easily. This cuts down on the conversations that go cold after a long catalog with no reply.
You base the main pick on the customer's need
The recommendation used to follow whatever the store was pushing or whatever had the most stock sitting around, with no real link to what the customer asked for. Now, with the main pick always tied to the need stated in the conversation, the recommendation makes sense for that specific request. The store stops pushing product and starts showing what actually solves the problem.
You explain the difference so the customer doesn't ask again
Listing products without explaining what separates one from another left the customer with no way to judge, so they came back asking which one was better. With a clear difference assigned to each option, that question gets answered in the first message, and the conversation moves forward without an extra round just to clarify what could have been clear from the start.
You lead with value before the customer hears the price
Leading with the price made the customer react to the number before understanding what they were buying. With the value of the main pick explained before the price, the reply already carries the reason behind that cost, and the "that's expensive" reactions, the ones that showed up only because the price arrived with no context, become less common.
You end conversations with a direction, not stuck halfway
It was common for a reply to lay out the options and wait for the customer to take the next step, which left plenty of conversations with no reply. With a question that helps decide closing every reply, the conversation keeps moving instead of waiting on the customer's next move, and the store keeps more conversations active until the decision is made.