U are not paying to cpf. U are paying to yourself the interest u would have earned if u didn't use cpf for house.
This is why the speakers are recommending to not use cpf for house if possible. Because not only you have to put back the accrued interest yourself, you also lose out the interest that CPF gives you. You dont just simply lose 2.5%.
Yes it belongs to us, that is why the interest goes back into our CPF account. This way, we will have enough for our retirement.
Why wait for 25 years when MOP is only 5 years?
Pay with cash and no interest