The idea is that a rigger is normally the Owner of whatever drones they are going to jump into. As the book mentions, when you are the Owner of a device, you are treated as having 4 marks (which is above the normal 3 possible through hacking) on any device you own; this means a rigger can always jump into any drone they own, as those marks cannot be removed unless you are no longer the owner. This Ownership benefit is something anyone can get, by the way, not just riggers. Even your adept has the Owner mark on her commlink.
An RCC cannot be used for hacking, as it lacks an Attack or Sleaze attribute. As such, you can't be marking and jumping into drones you don't own. If you want to do this, you'll need a cyberdeck and to pick up the Hacking or Cybercombat skill. At this point though, you're giving up your RCC (you cannot use both at once) and the benefits it offers you. It also requires a significant skill investment, so I do not recommend you do this.
Early into the game I would say that a R2 Control Rig is fine for early on. The one die different isn't worth the significant resource cost and Essence cost. You should spend that money on other things like your RCC, drones, a vehicle, and other augmentations depending on what you plan on doing.