TIAC - CRR's post said "On first contact pilot instructed to reduce speed/turn/etc.", so the 'listening in' option is not an option - and to suddenly find you are number 5 with no clue given before does change the way we do things. It might even be a turn which significantly shortens the APPARENT track miles - which can be a problem for us.
It would not take even the most stupid of us long to detect a busy sector, I can assure you, and I would hope we all keep Stumm, but the 'unexpected' is always better received when a LITTLE background is given. If there is a reason why I might need to level for a while, or even significantly reduce my ROD, say, at FL100 on descent to,?FL60? (maybe for a cabin pressure problem or whatever), or descend at 240kts all the way from FL330, I would aim to say a brief 'why' to you when I announce it, rather than your having to ask and interrupt my unfinished crossword.
It will help YOU plan too.