While I'm sure the US military sees the obvious possible logisitical solution for the island chains - and I've read them saying that in the past - that doesn't mean there's something deceitful going on here.

Before you make national security depend on a new, developing technology, and one that is also in limited supply, you give that technology a simpler, smaller mission to try it out and to develop it. That is, they don't want control of the first island chain to depend on Regent Craft all-electric sea gliders quite yet.