I suspect you get much more practiced and checked over answers that way.
In some contexts this would be seen as obviously a good thing. Specifically, if the thing you’re interested in is the ideas that your interviewee talks about, then you want them to be able to consider carefully and double-check their facts before sending them over.
The case where you don’t want that would seem to be the case where your primary interest is in the mental state of your interviewee, or where you hope to get them to stumble into revealing things they would want to hide.
Another big thing is that you can’t get tone-of-voice information via text. The way that someone says something may convey more to you than what they said, especially for some types of journalism.
I feel pretty sympathetic to the desire not to do things by text; I suspect you get much more practiced and checked over answers that way.
In some contexts this would be seen as obviously a good thing. Specifically, if the thing you’re interested in is the ideas that your interviewee talks about, then you want them to be able to consider carefully and double-check their facts before sending them over.
The case where you don’t want that would seem to be the case where your primary interest is in the mental state of your interviewee, or where you hope to get them to stumble into revealing things they would want to hide.
Another big thing is that you can’t get tone-of-voice information via text. The way that someone says something may convey more to you than what they said, especially for some types of journalism.