There's always some unnecessary verbiage in any IVR, but this little message seems to be the favorite. I've listened to some systems present this nugget for over a year without changing anything. It signals to me that no one is really minding the IVR store at whichever company I'm trying to get some service from.
When all IVRs were DTMF only the good ones enabled key ahead, the ability to press several keys in succession, without waiting for the prompt to play. Frequent callers to an IVR learned the keypress sequence to get them to their preferred transfer or function very quickly without having to listen to all the prompting. If the menu options changed, however, the speed dialers would up transferring to the wrong department, generating complaints back to the IVR manager. I think this was how the "menu options have changed..." phrase was born. The message may also reflect IVR managers' beliefs about why callers misroute. If the callers would only listen carefully to the options, the belief goes, then misroutes would be eliminated. It doesn't occur to some IVR managers that the prompting could be confusing or unclear. Thus, the phrase "please listen carefully."
Unfortunately, it's easier (process wise) to put phrases into IVRs than take them out. Power users, the ones who learn to key ahead, call frequently. And they don't listen to prompting. Playing the message for longer than a week is nearly useless, because the power users have already adjusted after a week, and it provides no information to occasional users. In speech systems it's even more useless, since you can leave the original menu grammars in place even if you change the prompting.
The message lives on, however, a legacy of another era and some magical thinking about how callers behave.