Two things:
1) The "gone to lunch" was an EXAMPLE of a reason why the phone's own user couldn't answer it themselves. e.g. if i'm scrabbling around under a desk it would be nice if one of my colleagues would answer a ringing phone via a DTMF keypress on theirs to pick it up rather than firing up their computer, firing up Call Assistant, and then transferring a call to their extension. Doubly so i'm not going to create a hunt group for all and sundry to answer my DDI calls and transfer my phone to it on the offchance that I might stray more than 15 seconds away from my desk.
2) If you think i'm telling prospective customers that they need a computer in order to have a desk phone, you're very much mistaken.