Allomantic metals are a "key" to investiture, not invested themselves, so I don't think it's weird that a metal that kills investiture wouldn't have any effect.
Idk if it's just semantics or not, but if you do that you're not really touching the investiture, you're touching the gemstone. The only place you'd see it's effect on raw investiture (on Roshar) would be touching sliver to stormlight itself. Or maybe Spren? That said, I guess the spores aren't "pure investiture" either, are they?
I'd be curious to see if as Sel evolves we start seeing cultures using silver weapons as a way to disarm Aeons.
**side note, I'm kinda new here, and I couldn't find any rules on posting. If I'm in violation of something, please let me know and link me the rules so I can read up!
