I have a card from my (Australian) bank which is linked to both my credit card account and my day-to-day savings account. When I use it in an ATM, I select which account I want to transact upon. It has been set up that way for probably twenty years.
I had a confusing conversation with one of my bank's call centre operators about what cards I have that suddenly cleared up when she looked at my records and exclaimed "Oh, you have both accounts linked to the same card. That's unusual. We don't do that any more."
It is a useful and convenient feature to only carry one card from my bank in my wallet. I can't see the downside for this feature. Why would they stop making this feature available?
I know "why" questions are hard to answer authoritatively, but I was hoping someone with experience with the industry could suggest what the bank's motivation for this might be.