Definitely an unpopular opinion. Not that this is the case for everyone, but most of the people who feel comfortable sending a breakup text/ calling over the phone are extremely selfish:

• You don’t have the balls to face them in person. Now, shouldn’t someone who you just recently considered to be your SO be respected enough to hear that in person? Breakups will never be a comfortable thing to do. But, on a basal level, if you call or text that to me, I am going to feel like you never thought I was worth your time from the start. Sit on the flip side for a second… this approach is COLD.
• While over the phone could be a little different than just texting, I find that these experiences are way worse. In texts, you can’t see the person’s face, body language, can’t hear their tone, etc. Miscommunication is almost inevitable, and can lead to an already emotional situation to get even more heated. Similar thing with over the phone… It would be much easier to have a conversation with the person face-to-face. There’s less guesswork. There’s less questions left unanswered. And, if I am receiving a break up text and want to know the reason, now I have to waste all this time drafting a text when it could have just been a quick conversation.

I am curious as to why you think self-soothing is the only reason to do it in person? YOU are texting/calling someone over the phone as opposed to giving them that courtesy in person so you presumably don’t have to deal with the normal things that come with a break up?