Premium Option credit allowed for T+0

As per your article on Zerodha, when the long/buy option positions are exited, or new write/short options are entered, the proceeds or credit of option premium can be used for only new long/buy option trades on the same trading day and only within the same segment (proceeds from equity options can’t be used for currency or vice versa). However, these proceeds or option credits can be used for other trades from the next trading day.

Can you explain why it is only allowed for buying option trades and not other segments? What is the logic behind this?