Malaya is too vulnerable, and it takes too long to secure. HK is far stronger for your later-game strategic defense (free NB), hidden square)
The opposite is the case for Malaya. Yes, it is vulnerable but strategically Malaya is the by far most powerful IC Japan can place.
I think you’re taking FIC as a given there. I can’t see how the Malaya IC is more powerful than FIC. Doesn’t need a naval base built to reach Calcutta?