In the advertising and marketing field, what is more important, the story of the ad. or the info of the product?

I think it depends on your target audience. For example, while the baby boomers are more interested to learn about the product info, the millennials tend to be attracted to the story of the ad, and consequently driven to learn more about the product.

Well this exactly depends on what stage your product is. If your product is known in the market and is in growth stage, ideally a story well expressed would be advantageous. If your product is in inception you may opt for product information &  story preceeds

I would say BOTH.

An Advert is just a bland piece of art without the story. What drives engagement is the story. However, your story should communicate the brand/product benefits or what we sometimes call USP for it to be effective.

An effective advert is one that can tell a brand/product story in an  engaging manner as to elicit a desired response from the target audience.

Technically, information on the product is more important however, the story is objectively important because it gets attention and generates attention as it glamourises the product and makes it something special. If you can include both you have a 50/50 chance of success or failure since the ad becomes too long.

It depends, you always have several directions to utilize design and creativity to deliver your message.  Are you launching a new product/service/company?  Are you promoting? Are you informing? or are you simply increasing loyalty?  These are all questions that answer the objectives you are aiming for.

Let's say you are promoting a new reduced price for a soda in the market.  The story is simple and brief, product and price (and maybe duration of promotion).  The rest lies on the creative layout which is a whole different story.  

On the other hand, your company is launching a new technology/app/software.  Here the content should be more informative and descriptive to showcase the products' attributes.

Also, lets say you are launching a new business.  A story is important to make that instant connection with your target audience.

So it really boils down to your objectives and what you need your product to achieve.

Hope this helps. 

Both are. It's always a unique synergy/blend of USP and ESP. 

Unique Selling Proposition - Benefit and Emotional Selling Proposition - Home Truth/insight.