Sales is not any easy job, but it is very rewarding. People that do well in sales are those that take the time to understand their prospective client and their needs. People that struggle in sales focus on their product or services more than their customer. As a salesperson you have to learn to ask questions and be willing to listen to what your customer has to say. Answering questions with a question is one approach that could set you up as a salesperson to better understand your client and get more information. This technique sets you up to get more information than what you would by just answering the question with what you assume to be the best answer instead of gathering more information and getting a better understanding of the true needs of your customer.
By answering questions with a question you are now digging for the real issues or pain that the customer has to get a better understanding of what it is that they are truly looking for. This might not happen just after one question and it might take a series of questions to get a better understanding of what they want and are looking for. This is often weeding out smokescreen questions in which the prospective client is not getting to the true pain or reason that they are coming to you, instead they are trying to set up a smokescreen to not just come straight out and say what it is that their pain or problem is. If you just answer the question straight up then you are boxing yourself into an unfavorable selling situation that you have little understanding of the true reason that the customer is there for. The problem with this is you really don’t know enough about the prospect to be able to adequately address their needs. Through answering with questions you are digging deeper and getting a better opportunity to understand your prospect and their needs, rather than assuming what they need.
I totally agree that the salesman that don’t produce in a manner that they should are those that focus on the product over the customer. Finding the customers true need will create a relationship that can benefit both parties and make a prospect feel heard. This need finding is made much simpler by as you said answering a question with a question.