Assuming the MH alternative would still be available in case of a late cancellation (and you'd not mind spending the extra money for it), on such a relatively short flight, I'd say it's a risk worth taking, especially if Scoot is cheaper than MH. And the the flight would be cancelled, you'd probably see it at least some hours in advance (aircraft not incoming from SIN)

I do see you're One World Plat, so you'd get Elite treatment when flying with MH. Now the lounge in KK isn't great, but it's better than waiting at the gate, and in KUL you'd have access to the regional lounge, which definitely is a solid product.

In your case with Elite status, I'd probably pick MH over Scoot if the flight costs are the same or even MH is slightly more expensive. Without Elite status, I might prefer Scoot unless MH is cheaper.