It might increase conversion in terms of adding to cart, but it might not translate to increase sales (the real conversion you want). Your product quality, customer service and providing the right product information to your customer is what will convince them to buy.
There is simply not enough information in the product listing page to decide if the product is worthy of buying. Because the image is too small, no reviews, no product info, etc.
Furthermore, having so many CTAs in a page will make it visually distracting.
An alternative is using hover states to show the CTA. Or preview the product in a lightbox so the user can see more detail and add to cart. This also allows them to keep browsing for products.
Finally, as mentioned by adamsoh, there are some instances CTA in product listing page makes sense. It allows users who do not need to see or judge a product (because they are already familiar with it and bought it in your store or at many other places before) to add to cart and purchase quickly. Also, in cases where the cost of buying the wrong product is not too high.