Is applying stain on all sides of decking & framing lumber beneficial?

Is it beneficial or harmful to apply stain to all sides of wood decking and framing material possibly before boards are installed. This deck will be full sun in a high humid tropical like climate. The deck itself is appx 4 ft above grade. Decking and frame will be constructed SYP ground contact treated lumber. Was planning to use Cabot Australian Timber Oil but after reading multiple posts I am leaning towards the TWP100 or Resore-A-Deck semi transparent for the decking and a solid color stain for posts, framing & hand rails. Please advise your thoughts.