Building Websites vs. selling Domain Names.

I used to build websites for clients and would take sometimes up to a month to get the projects done, sometimes longer and you would have to add content, logos, information, social media and eventually, you would get paid. Versus having a domain name, a generic descriptive domain name and just selling that domain name. So what I came to learn or realize is having a descriptive generic domain name or website name was more valuable and you could sell it in a shorter period of time than building out a website.