I have not said requirements are not in place. I said it is unlikely to be asked for the 500k. UNLIKELY is not NEVER. The fact I and thousands of others have not been asked does mean something, it is confirmation of the rarity of being asked to show 500k.
Sponsorship is usually for dependents, kids/wife/husband. You would need to contact Jakarta embassy if they allow adult sponsorship. Probably easier if your father 'loans' you the 500k and apply yourself.
Anonymous participant it is his direct way, he does give good advice but the delivery can be sharp for some. You are fine, don't worry about the 500k, have 20K cash just in case.
No need to be nervous, 100s of DTVERS depart/enter daily overwhelming majority face no question. If you don't have 500k readily accessible in the unlikely event of it being asked for, having 20K in cash along with accommodation booked will go a long way to ensure entry. I've never been asked in 5 entries.