Kamon-san wrote:That's the answer I feared/expected. I'm all too aware of convenient story writing and things only popping up in one episode, never to be shown again.
It's not an answer to be feared. In-universe it even makes sense. The only part that's "whatever's convenient" is the fact that we don't know what modular component was picked to be in the pylon until it becomes relevant.
I don't know if I should find what I'm about to say ironic or not, but I've always found that in most cases where something is described as "convenient to the plot", it's nearly always something that I thought was much better that way. When I was reading the entry on TV Tropes for New Powers as the Plot Demands (before I stopped going to that site habitually), I found the examples to be cases where I actually
liked that the thing in question wasn't explained, because that made it just so much
cooler. (Of course TV Tropes is quick to point out that Tropes Are Not Bad, but I'm used to "It's convenient to the plot" being considered at best an accepted flaw implying that having an ironclad justification properly foreshadowed is always better.)
The example that comes most immediately to mind is Goku in the Freeza arc of DBZ using a mind-meld technique to learn everything he needs to know from Krillin to get him up to speed after he shows up on Namek. It was a new power as demanded by the plot, one
he didn't even know he had until he just kinda did it and it worked... and that was the
best way it could possibly have been presented. Not only did it (of course) facilitate the plot by removing an uninteresting complication, it really made an impression, expertly selling Goku as the holder of mysterious power even
he doesn't know about yet understands intuitively when it comes to him -- because he's
the natural. (And it was thus an excellent buildup event to his SSJ transformation.)