There are numerous articles I’ve written where a certificate is a prerequisite for deploying a piece of infrastructure.
In addition to the operational benefits of managing SAN, it is also becoming more necessary at the client level with browsers like Chrome 58 and Firefox 48 that don’t trust certificates without this specification.
If you just need a simple self-signed certificate where the Subject CN is sufficient to denote your public hostname, then read my article here instead.
If you manage a larger internal environment and want to create your own trusted Certificate Authority so you can provide trusted SAN certificates for multiple groups/services, then read my article here. These also provide better support for full browser trust.