Why is mailing a letter in Singapore so complicated?

SINGPOST should not complicate the simple task of mailing a letter.

Stamps dispensed by machines do not state the postage value. Originally, stamps used to merely show Local for mail to Singapore addresses. Recently, this has been expanded to 1st Local and 2nd Local stamps for use depending on the staggered weight of letters.

But to the uninitiated who buy stamps at a machine, how are they to know which stamp they should use. In other postal administrations, First is associated with priority or express delivery but not in Singapore.