Good idea if they're fighting Malaysia. Not such a good one if they're not.No,singapore quite sensibly regards actually fighting in its own city as having pretty much lost the war. It instead plans to quickly attack north,which is why its SPG systems for example are much narrower than those of many others-they are designed to fit the narrow tracks of malaysian plantations.
(Granted, Malaysia staying out of the war if someone else is landing in Singapore probably means Singapore screwed up...)