Right now, Monday.com has the ability to customize what email notifications you receive. If this feature were to also be available for the notifications within monday.com then it could create a powerful way for teams to stay inside of monday.com and not need additional apps like slack.
If a user is on many boards the bell notifications almost become pointless because the user is being notified about tons of items that are not necessarily relevant. If a user could adjust notification settings at user/account level, and at a board level then the bell icon could be very powerful.
If the inbox messages could also be customized instead of having replies to updates be pushed to the bell, but rather go back to the inbox, it would streamline communications.
See this loom video for a further explanation Loom | Free Screen & Video Recording Software | Loom
These changes would make it possible for monday.com to replace slack and trello.