The latter is a negotiation tactic given in "Never Split the Difference". Essentially communicating over text/email allows you to carefully think about your words, whereas over a call or video call you can read tone of voice, body language, etc. and throw people off balance and reveal info.
I’ve seen recruiters “leak” a lot of “confidential” information from their clients saying “I’ve been asked not to share this but…”. I’ve always taken such messages with a pinch of cynicism but typically such messages are corresponded by phone where an audit trail is less more easily deniable.
So I definitely think phones are used because it allows the rules to be bent in a multitude of ways with a lower risk of consequence.
Plus it’s easier to pressure people when you’re on the phone than it is when they’re emailing.
Yes this. I see a lot of elaborate ideas about why recruiters prefer the phone, but it's simply playing to their strengths. It doesn't even need to be nefarious, everyone in the world plays to their own strengths in life.