600 SGD goes a long way in those countries.
Good housing will cost you.
The actual criteria to get a permit doesn't seem too onerous [1].
There is a concessionary rate for the work permit levy if the household has young children, elderly, or disabled people though [2].
[1] https://www.mom.gov.sg/passes-and-permits/work-permit-for-fo...
[2] https://www.mom.gov.sg/passes-and-permits/work-permit-for-fo...
Singapore is an orderly country and there is some institutional support to safeguard the working conditions of FDWs. However there is a power imbalance between employee and employer, and the FDW may not know her rights, or it may not be in her short-term interest to assert them.
Additionally, many FDWs are employed through agencies who will usually prioritise fee-collection over FDW welfare.
Generally speaking FDWs are pleased to have the opportunity to work in Singapore as it is 2-3 times what they could earn at home, but they do hope for a "kindly" employer.
Other countries do not have such a good reputation. Philippines actually banned Saudi Arabia from hiring domestic OFWs because of cases of indentured servitude, abuse and murder.
Between that and the poor living conditions, it's indentured servitude for the time of their contracts. Absolutely awful.
HK is doing much better and has stronger laws to protect domestic workers (actual day off, etc...), Singapore is catching up but in other countries it's extremely sad.