The questions needed to be asked about any feature:
1) Does this feature make product/game, a more user-friendly?
Meaning, will it be more easier to play, get information, etc.
This one (and others) does.
2) Does the feature harm the game essence?
No it does not. Being bored to death to find looking at a single page and refreshing it once every few seconds is not the essence of this game.
It is most definitely not a criteria for a BB manager.
It will make the game "easier", but on the other hand, no one will suggest something like "changing the time of the auction to be 10 seconds".
This will make the game "harder", but as no sense as it does not make you a better BB manager if you have 10 seconds instead of 3.
So, again, making a game easier is not the question, but does it make the essence of the game easier.
It most definitely does not.
3) How much will it cost?
Adding a refresher is VERY simple.
Adding a buzzer sounds almost as simple.
4) Does the cost worth the hustle?
Yes - low cost, nice improvement for making the game more user-friendly.