> I disagree re: obscurity. I think the reply interface was updated (2016?) to the current layout for replies. We have had very few accidental group replies as a result of the layout. I think it helps tremendously with that and mirrors the private reply option on a few other widely used platforms. Especially on a mobile screen, it's very easy to locate.
I can see it helps you, but some of my users are on unable to find and use the feature. All the other platforms I use have a Reply to sender option rather than Private - including group.io when using email Further, as someone who normally uses email when I tried to find the option on the web screen it took some time, if was average user I would have given up and assumed it did not exist.
> I can see how with large desktop screens it may feel too far away, not sure there is a fix for that
I think my last suggestion is a good solution. Replace the greyed out Private button on the right by a Private check box on the left above the reply button. It would be much more obvious and I don't think would make it more likely for people to use it by accident.