Answer:
Bank 0 registers are more likely modified during the execution of user code not during initialization and hence they have been named as User space registers. On the contrary, bank 1 registers are more likely modified during initialization not during execution and hence they have been named as configuration space registers.
For example,each digital block has the following 7 registers:
Out of the above 7 registers Function,Input and Output registers are placed in Bank 1 and DR0,DR1,DR2 and CR0 registers are placed in Bank0.