Through enhanced ecommerce you can capture more ecommerce data.
You can send only two types of ecommerce data via traditional ecommerce tracking to Google Analytics: transaction data and item data
Through enhanced ecommerce tracking, you can send following types of ecommerce data to Google Analytics:
Impression data: Total number of the product shown to the user on the Home page or category page
Product data: Product detail view. Product attributes like product name, product id, product variant, product colour, product brand.
Promotion data: Internal Promotion ID, promotion creative, position, coupon code
Action data: product view, add to cart, remove from cart, checkout, shipping method, transaction
In short, through the standard ecommerce tracking, you can only track users’ transactions on the order confirmation page. Whereas through enhanced ecommerce tracking you can also track all the steps (like product view, add to cart, remove from cart etc) that were taken by a user before the purchase.