This is doing numbers, so to maybe preempt the most common responses:
1. "Or you can ask if it's okay" - sure. Go ahead. I just wanted people to be aware of a privacy-preserving option that has the same convenience as just giving out the number. As long as you don't give out my info without consent, we're good.
2. "You know about phone books, right?" - Yes. They sucked. Good riddance. "We used to be even worse at privacy" is not a justification. The world changed, mostly for the better.