"Phono" Cable - Necessary if you have RCA outs?

Its just terminology, as far as I remember. RCAs at one point were often called phono jacks/plugs. Specialized cables that use DIN to RCA are sometimes called "phono" cables because many tonearms with changeable interconnects use a DIN at the tone arm end. Whether or not an IC is good for your tonearm-pre connection is a matter to do with system synergy, not terminology, as long as you can make the right connections.

Agree, just terminology. Interconnect, Interlink, phono cable, patch cord, yada yada.

XLO, Purist and a few others make and market special phonocables to go from your arm to your pre-pre or preamp.
Usually they are expensive, but worth your while if you own a very high resolution vinyl system. In fact, there they are a must. I don't know what your system is, but if you're curious and live in the States, try to borrow a pair from the Cable Company and find out for yourself. (www.fatwyre.com)

I think the key word here is market. If you believe that the megabuck ICs offer good value, then you'll want a megabuck "phono" cable. I have no idea if they are worthwhile.