During the industrial revolution a practice sprung up amongst unscrupulous bosses of paying wages in tokens forcing their employees to use company shops for their provisions, both work-wear and tools and also domestic stuff like food. These were often poor quality at extortionate rates and were manipulated so that the workers never built up savings to enable them to better themselves. A series of laws were introduced to put a stop to this practice. The 1725 act required employers to use coin of the realm and the 1831 act stopped the practice in many trades and virtually all were protected by the 1887 act. Navvyman by Dick Sullivan has a good chapter on the subject. That didn’t necessarily stop the practice; intimidation of workers and forcing other local traders out of business was not uncommon.
It looks like the Royal Bank of Scotland is trying on something similar by forcing their staff to use an in-house bank account. There is no suggestion that there is any profiteering, traditionally bank employees have obtained financial services such as mortgages at a discount, but the practice is still against the spirit of the law if not the letter. It would be very prudent of an employee to hold their savings in an account separate from their employment so that in the unlikely event of a failure, they don’t lose out on both sides. In the same way it is not wise to invest too heavily in company share schemes.