Accessibility is the process of removing barriers to meet people’s access needs. It goes hand in hand with usability, affordability, availability, and overall good design. This article focuses specifically on visual barriers in typography.
Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.
Proof of concept in software development is a controversial topic. The person that came up with a software idea is usually convinced of its relevance. And stakeholders usually don't want to spend time on something that is not even going to be included in the final product.