You seam to talk about something complete different from what the article is about. This is about a web store storing end users passwords in clear text in their database, not your internal system for employees or what ever. For a web store there is no reason what so ever to use the customer provided password for anything other than authenticating the user for the web service, all other access deeper in the system should use credentials set up between these services.
And even for you set up there is no reason that some deep back end have to use the same password for user X than user X typed in when accessing the web service, if you must need per user passwords inside your system then let the system auto generated credentials upon account creation for b2b authentication.
Successful and fortunate crime is called virtue. - Seneca