Ad hoc, accidental communication simply doesn't happen in remote work environments.

Coffee breaks are a shockingly productive element that simply work better in person, at least in my experience (and this seems to be a common sentiment at my software company).

In-person conversations don't have technical difficulties, there's much better engagement which allows people to better read the audience and adapt presentations/design conversations appropriately.

Surveys among colleagues seem to agree -- hybrid seems good, remote only simply is not as productive nor enjoyable.