Higher Returns: An STP allows you to transfer money from a debt fund to an equity fund and vice versa. This allows you to get the higher returns from the equity fund and at the same time, part of your investment is protected.
Rebalancing: Another benefit of investing in an STP is that it helps you in rebalancing your portfolio as it allows you to easily reallocate funds from your debt fund to equity fund and vice versa depending on the market.
An STP is similar to a SIP and similarly helps in averaging out the constituents of the investment.