What’s special about the ffprobe command redirection?

When I wanted to redirect the stdout of the ffprobe command, I got a surprise: the usual stdout > (file) didn’t work. After a few web searches, I found the answer: I had to use stdout > (file) 2>&1,
and it was OK: https://stackoverflow.com/questions/29680391/ffmpeg-command-line-write-output-to-a-text-file.

What could explain why the usual method of redirecting output to a file doesn’t work for me: the version of ffprobe I’m using? The shell? Or something else?

~$ ffprobe --version
ffprobe version 5.1.6-0+deb12u1 Copyright (c) 2007-2024 the FFmpeg developers
  built with gcc 12 (Debian 12.2.0-14)

Or is it up to the programmer to choose the way a redirection behaves, as explained in this comment:

 @Apostolos it's up to the programmer, you may want to keep normal
 output separate from error output.