Why does Dapper need a reference to the transaction when executing a query?

Just looking through this tutorial: https://www.davepaquette.com/archive/2019/02/06/managing-transactions-in-dapper.aspx My understanding (without Dapper) is once you have a connection, you can open a transaction, then execute a bunch of statements, then either commit or roll back the transaction. Those queries don't need to reference the transaction because the connection already 'knows' about it. So why does Dapper need the transaction every time some action is performed?