Advantages of transferring existing regular MF to Direct MF

Yes, there is. By investing in direct plans, you will automatically get higher return as compared to the regular plans by virtue of the lower expense ratio in direct plans. For example, if you were investing in Aditya Birla Sun Life Frontline Equity Fund, the expense ratio of the regular plan is 2.18%
and 1.31% for direct. So by investing in direct plans, your returns will automatically be higher to the tune of the 0.87%.

The new LTCG rules will apply.