First off, let me say that I live and breathe the terminal. Almost 2 decades playing in unix and linux gives me a strong love for it. I know I am more productive than a pointy clicky loser. BASH ftmfw! (and when I am stuck admin’ing windows systems, powershell, which I am not ashamed to say I have a newfound fondness for.)
So, you are studying for a networking certification. Maybe CCNA or CCNP, maybe F5 or Juniper. You need multiple interfaces to run GNS3/Dynamips or your favorite networking tool. Alas, the default configuration of VMWare Fusion just has the basic VMnet1 and VMnet8. Here is how to fix that!