@VenuMadhav Yes, this is a real world use-case. I have built my entire portfolio this way, all thanks to ICICIdirect. I have now been doing this for 5+ years.
Not everything is black and white because investors want full control over their funds utilisation so there is a lot of room for customisation.
Lets say I had a big day today (trading) and I want to reduce my funds borrowed in my long term portfolio. How do I do that in Zerodha? Then of course, I will need a part payment flexible option.