If you are maintaining e-commerce website/store with following Google webmaster guidelines carefully and using secure payment methods to ensuring that customers could formulate purchases in the ways they want.
E-commerce website/store business owners must attentively keep on top of all an e-commerce website and ensure that Google and other major search will show their web pages at first.
In modern era web design are constantly changing according to modern trends and this could also impact your search engine rankings and leads.
For example your website main page have Image carousels then that should be light weight (minimum slides) which will not affect website speed otherwise that would frustrate the users and user will leave without finding important information.
Design problems like these can guide to customers throw out their shopping carts these causes can reduce your search engine optimization so, optimization of e-commerce website/store is very important.