"Would you prefer to not have the choice to have access to this feature, and prevent others from having it too?"

Yes, I would prefer that. LinkedIn has not shown itself to be a particularly good or careful actor in the past, and now, even if I don't opt in to this, my email to people using this feature runs through LinkedIn servers. There are always third parties between me and the person I'm emailing, but as the number increases, the likelihood of compromise or failure of delivery increases.