By default, Rewards are enabled. Rewards can be disabled inside the web app. If Rewards are disabled, then team members won't see coins inside Slack or Microsoft Teams.
Who can use this: Workspace Owners and Admins on the Pro and Enterprise plans, or on any plan during the free trial. Works the same for Slack and Microsoft Teams workspaces.
For an overview of the whole feature, read the Rewards Guide.
Enable or Disable Rewards
Open the Web App.
Go to Settings, then the Rewards section.
In the upper right-hand corner, click Disable.
Note: To turn rewards back on, click Enable Rewards.
Related: Disabling reward types and categories and Rewards report.