Is there any evidence to suggest that a prettier more professional design results in the user trusting that site more and therefore that website results in better sales? Are there any examples of this?
For example, Marks & Spencer spent 2 years redesigning their new site – and reportedly spent an enormous £150m on it. By the time it launched, it was already outdated. Furthermore, its online sales plunged by 8.1% in the first quarter following the launch of its new website. Reference: https://econsultancy.com/blog/65244-where-did-the-marks-spencer-website-relaunch-go-wrong.
This is a small example but I'm curious if, for example, http://www.worldofenvelopes.com/ improved their design to be more appealing and professional would this increase conversion rate due to users trusting the site more and is there any evidence of this?