@Dr_badger
In Word, "traditional" comment balloons appear in the Markup area, that is, in the same location as that of revision balloons. Many formatting options are available in those comment balloons.
With the new design of comments, so-called modern comments, a lot has changed. Formatting isn't supported in the same way, for example. A requirement to post comments has been added, and the purpose is to prevent people from seeing what you are typing until after you have posted the comment, in a document which is being co-authored. See also https://insider.office.com/en-us/blog/modern-commenting-in-word.
I seldom use comments in Google docs, but at least on the surface, the new Word comments seem to be similar to those.
