Looks like an excellent place to store munitions.
The deck looks great. I love the non-orthagonal edges of the wood butting up to the concrete. It gives a nice organic feel to it. Much more visually interesting than a typical circle, oval or rectangle. I know that's mostly driven by the original shape of the pool, but it looks nicer than I thought it would originally. For added accenting you could add a few planter boxes too, but it really did turn out nicely.
And yes, that looks pretty overbuilt, which is good.
Is there any provision for ventilation under there? Just through the slats (should be adequate).