
for me...it is the
1) ease of moving monies to investment assets in FSM and out (temporarily)
no need to goto banks to transfer monies (if more than allowed by online transact limits)
2) no lock in period where else FD has minimum (1 month?)
3) FD has higher minimum amount for initial investment...CMF RM 500
4) FD has higher subsequent reinvestment amount...CMF RM 100
5) FD has higher withdrawal redemption amount...CMF is RM 100
6) can view my non investment monies (CMF) and investment monies (FI/EQ) at a same page in FSM
for more info.....
http://www.fundsupermart.com.my/main/faq/faq.svdo?id=9718#1 
some drawbacks I can think of...
1) FD can get monies FAST (if on working hours)....CMF have to wait a few days.
therefore one is recommended to get Saving & FD a/c too...just incase one needed to get faster.
2) .....
Thank you. That answers it.