Few months ago when launching apps on Mac Os became sluggish because their telemetry service had high latency -- that was the moment I lost faith in all of Apple's privacy claims.
PS: Still use a MBP, iPhone and an Apple Watch. :(
That telemetry could easily -- more easily in fact -- have been done in a privacy protecting way: have your machine ship with a signature database and then have it randomly and frequently download deltas. Then check the signature database locally. It would be faster too. Especially on the mac we're not talking about an enormous database.
Rather disappointed that Apple didn't take this route. They do do something similar with their virus database (XProtect).
That "telemetry" (which is misleading in the current context) was about checking for malware. I'm talking the specific case of launching apps on macOS.
Part of the issue IIRC is that application names were exposed in the request, not encrypted in any way. So there are legitimate privacy/security concerns in publicly announcing every application that you open on your computer.
PS: Still use a MBP, iPhone and an Apple Watch. :(