Digi Postpaid Plus is another plan to make more money from the customer.
It suits those who are "balance" user, ie use same amount of SMS and voice call every month only.

For those who are heavy sms-er or use voice call more, you will have to pay more! For example, for the old DG50 plan, for pure voice call user, one can make up to 384 mins voice calls; but for the new DG48 plus, one can make up to 200 mins voice calls only, subsequent usage will be charged accordingly. --- Vice versa for SMS and MMS also.

This is actually another marketing tactic by Digi - New plan = customers have less flexibility to decide on how they going to utilize their monthly commitment.

simple. They afraid you "run away" with the phone after you subscribe the plan. (you get a phone at cheap price if you subscribe the 1 or 2 years plan)

so, they charge you in full first, thats include device advance payment. the advance payment will be given back to you on monthly basis throughout your contract period.

therefore, in case you 'run away' with the phone, digi don't have to 'beg' you to pay for the termination charges so hard.