I flew both pax and freight for SIA, give me freight anytime, no hassle, no drama. Only drawback is that at some stations you tend to be left to your own devices re transport etc. as there are, just occasionally, no SIA traffic staff on duty at your time of arrival/departure, its been arranged but sometimes the wires get crossed! Only very rare anyway so not really a consideration. Not everything you carry is either a refrigerator or a F1 car, you will also carry quite a lot of essential supplies to the oil and other industries.
Should add that in those days there was no separate cargo contract or company.