I work for a large RX retailer with 7600 stores and we rarely use the Feature 630 and pre page tone on our phones. The pages do get across loud and clear without a tone.
Our newer stores are using Cisco sets and ironically these make a dialpad #3 DTMF beep across the loudspeakers before you make a page.
Meijer, a Midwestern Hypermart chain, uses Avaya pbx systems and they have experimented with paging controllers that either Chime or Beep before you page, it just depends on which Meijer you are at. Most Meijers have no page tone at all though....you just hear a pop when the controller connects and a pop when the page releases. Kind of backwards through...the Nortel phone paging of the world releases without a "pop".
Meijer used to use ROLM 9600 systems in the 1990s...the digital service desk sets would page without an announce tone while the analog sets would make a distinct DTMF 9 tone before you'd talk....really screwy.
Union Pacific Metra station down the street here in Chicago uses a 3 tone chime before station announcements are read, while Union Station uses no tones before the announcements. Passengers get the point either way.
I don't see how a tone or chime could hurt....but I don't think its imperative to a proper paging system.
By the way, my name GordonKapes is in reference to the 2 Gordon Kapes MZ4 paging controllers I was given by a tech in the field and I hooked one up in my residence. It gives you the choice between single or 3 tone page tone or no tone at all. Apparently it was one of the best paging controllers ever made...but GK got out of the business years ago unfortunately.