More than ASBA, I think what is being considered is how mandates work IPO using UPI. Tough to see how something like this can be implemented where there is risk involved (intraday trading, F&O, etc.). In all likelihood, I think this will be mostly for equity investing, where time is not of the essence. So allocate funds, get a mandate request through UPI, and place a buy order to invest once blocked. Similarly, first, block the security and then place a sell order.
I don’t think this move would affect the broking industry much; in any case, most equity investors withdraw funds themselves, or brokers send them out once a month. There might be some loss in income, but this will also mean a much lesser compliance burden and costs. Most people around us invest passively, and brokers might welcome the move if using this mechanism to invest reduces the compliance burden. I think the mandate route will be optional; otherwise, customers will not be able to place orders when the banking or UPI system is facing issues.
Today customers use brokers not just for execution; it is for everything from offering a trading platform to reporting to handling customer queries and reducing system risk. If exchanges can do all of these well, then brokers become redundant. I had written something earlier.