Password data items are just there to mask sensitive data and to ensure it is not logged. The data that stored in a password data item might not even be a password, it might be a senstive customer data field that, as part of a business process, needs to be manipulated in some way in a calculation stage to be used.
Also I once came accross an applcaiton where the new password had to contain certain characters from the old password - so the new password needed to be calculated based upon the old.
For these reasons, and others, the ability to manipulate data stored in password data items in calculation stages is a requirement of the product that will not be removed.
The expectation is that no one will have access to Studio in production so casting passwords into text will not be something anyone can do in that environment. In a development environment where develoeprs are using their own production credentials - because platform security is not in place in development to protect their passwords then a process (such as removing credentials each day) is the only option open to them.
Entering a few credenals in Credential Manager would take a couple of minutes so I do not see that as being a developerment overhead.