I'm building a lead-gen automation system. Once I've scraped leads and gathered the necessary info, is it better to start with cold emails or hit them up via a WhatsApp chatbot that engages them conversationally, qualifies them, and guides them toward booking a call?

Let me think about this. If the idea is to get people into a chat with an agent when they've never talked to you before, that would probably not work very well — if you've never talked to somebody and have no connection with them, you're cold, and the last thing they'd want to do is go into some chatbot sequence. The whole point of cold outreach is implying that you personally are doing the outreach; if you funnel them into a chatbot, even one pretending to be a real human, the probability that works is pretty low. I personally treat leads like gold — I give them a ton of value upfront and deal with them myself; I don't actually use AI to talk to my leads. People react really badly when they feel conned into thinking they're talking to a real person but it's actually AI — I had someone in my community blow up at me over a message they thought was AI-generated (it wasn't, I'd just misread their name/gender), and that visceral reaction is worth avoiding, especially without a good relationship with the lead already.