The North Americans (USA and Canada) have an aversion to metal, and thats probably for a good reason. Here in Australia it is much more common to find all-metal telescopes, partly because nice wood is expensive. The problem that might arise using metal is expansion/contraction as it heats up with the ambient temperature of the day then shrinks again as it cools at night time, much like the glass in the mirrors. While its changing, either expanding/contracting, its not good for the optimal operation of the telescope (eg, you can use it but you wont achieve the best image possible until it has reached ambient temperature). North America can experience large temperature differences during the day, which makes wood a better option, but here in Australia the daily range is not always that large. As I see you are in a tropical area, I guess your temperature difference between day and night would be relatively small, so an all-aluminium metal scope would probably work ok.
