Once someone owns a relevant and search friendly domain they will have it for a long time. It may never become available again. Domains can be seen as investments. If you no longer need a domain you can sell it years later, often at a profit!
Search Engine Optimization
Exact-match domain (EMD) names match the exact searched keyword phrase of the user. If you’re looking for carpet and you live in Miami, you might search “carpet miami”. CarpetMiami.com would be the exact-match domain name.
Immediate Brand Recognition
Users implicity trust good domains like brands. Domains that are not able to be pronounced are hard for customers to remember. It is easier to remember a short phrase than abbreviations of several names or services.