Thank you for your respective replies.

For Public Bank, on which specific date will Standing Instruction be executed by the bank, for the deduction from my savings account to pay for the monthly instalment?
The following clause is stated in Public Bank loan offer letter.
Does it mean that fund deduction from my savings account will occur on 1st of every month?
It is understandable that different people may have different views on the payment of monthly instalment. For me, I will treat manual payment of housing loan instalment as my monthly obligation, similar to monthly payment of credit card bills, utility bills, rental and so on. I do not think that it is a hassle, instead I view it as one of my monthly responsibilities that I should perform.
No matter what happens, the bank's interest is always protected, regardless of whether the payment is made via Standing Instruction, or manual fund transfer. In the event of late payment or non-payment, the bank will definitely charge late payment changes.
If I manually transfer the money from my savings account to the loan account, for the payment of monthly loan instalment, under my own effort, I can be absolutely sure that I have paid monthly loan instalment.
Let's say that I have sufficient fund in my savings account. If Standing Instruction somehow fails to be executed (for some undisclosed reasons known only to the bank), there may be late payment changes. or loan interest being increased by the bank, even though the glitch is attributed to the bank. I do have concern whether the bank will execute the Standing Instruction, or not.
So, I prefer to have my own control of payment of monthly loan instalment. The onus is on me, to ensure timely payment of monthly loan instalment, and to avoid late payment changes.
Then again, if the Standing Instruction is mandatory, then I have no choice, but to abide by the terms and conditions set by the bank.
Thank you for your reply.

I do have a savings account in that bank. However, I prefer to have my own control of payment of monthly loan instalment, as in when I pay the monthly instalment, as long as it is before or on payment due date.
In my opinion, is better to manage your own payment than to give instruction to 'others to access your funds' .... be it SI or Auto Debit.
Have a fix date monthly and alarm set to pay all bills.
Log-in into the account frequently will help to detect any unusual transactions, if any.