It's been implied that Krishna is so much more advanced than the current technological level of the universe that they don't even understand how it works. The basic technologies are the same, but the level of miniaturization and optimization in Krishna's systems is literally not replicable with current technology. It can be inferred that Krishna was considered an "endgame" ship in the game, since Hiro was a long-time hardcore player.
Iirc his concern is more about spareparts, the ship is too rare if it broke, he's done for. This is also why he is looking for a mothership too as relying on his starting ship limits his options, like unable to pick up loot or repair on the go. There is printing, but only limited to food and for really good stuff they have to go to the experts anyway.
As mention in the previous chapter, there are already prototype ships out in the story that could in paper rival Krishna, there just no good pilot that can handle them.
Elma's backstory is actually pretty predictable. There's no mines lurking in the depths or anything.
He gains more than he loses, really. Ships need maintenance, so he has to let someone look at it sooner or later. And the Krishna isn't a Lost Ship or anything. She's a really good ship, but not isekai hax OP. Hiro's insane combat skills and unconventional tactics, drilled to perfection in a world where death is barely an inconvenience, have much more to do with the ship's performance. The piloting data is worthless because no one else would DARE fight like Hiro does, and that makes the Krishna a lot less interesting.
That's assuming the society can even replicate the tech.
From her reactions though...... doesn't seem like a reward to me
