I worked briefly at a call center for a company I won't mention. We had that system in place so people could punch in account numbers and we were supposed to get a popup on our screen with all of their info on it. It literally never worked. They'd punch in their numbers, but the popup never appeared once. When my trainer was explaining it to us, all he had to say was "yeah sometimes it works, sometimes it doesn't" and there didn't seem to be any concern about getting it fixed. And callers complained, too, so it wasn't like nobody noticed!
From a higher level view at a company that that has a center that customers call into, that strategy is used to create a compliant cooperative customer. Especially if most of them call in screaming. Especially if you might be giving them bad technical or financial news. Presumably it filters out those too angry to type in numbers, while making people in hopeless out of control situations feel they have control in that they're typing in numbers. Its a psyop, mostly.
If you let customers type in an account number, for example, people will type in random numbers with a slight preference for numbers beginning with 1. However if all your real account numbers begin with a 400, then you can programmatically exclude all calls with accounts entered that don't match a regex of begins-with-four-zero-zero. That filters out cranks and people who are unqualified to even call. If they enter zero, 9, 1234, just dump them to dialtone. Superficially it sounds like bad security for your seven digit identifier to really be like 4 digits of security because they all begin with 400 but its actually a feature for filtering.
