[Homura7]

Spoiler for spoiler:

Looking at the way Arca speaks to Cruz, I'm starting to think this hasn't anything to do with the chip but with something of much greater importance

Because let's think about it for a second. If Arclight wanted only the other half of the chip, then why he didn't use Blackout Invoke on Arca earlier? It's very clear, at least to me, that he decided to use it now upon finding she was hiding him something, and that something has absolutely nothing to do with the chip but with Cruz himself.