Right. I didn’t think we’d been talking about contact tracing. The linked article was talking about “contact discovery” in the context of contact list scraping by messaging apps (like WhatsApp/Telegram/Signal), not about COVID exposure contact tracing...
Now that we are though, if I were a contact tracer, I’d totally ask to see your text messages - there’s a reasonable chance that while not everybody you texted is someone you came into contact with, there’s also probably a fairly high correlation the other way - if you had met up with someone you quite likely messaged or called them to arrange if. If it was my job to help you remember all the people you’d spent time with in the last 2-3 weeks, I’d definitely like to go through your messages and call logs to remind you about anyone you might’ve forgotten.