ch02: aggr. tx: add tx batching, saving in fees and exchange withdrawal example

ch02.asciidoc

@@ -134,7 +134,7 @@ Another common form of transaction is one that aggregates several inputs into a
 .Transaction aggregating funds
 image::images/mbc2_0206.png["Aggregating Transaction"]
 
-Finally, another transaction form that is seen often on the bitcoin ledger is a transaction that distributes one input to multiple outputs representing multiple recipients (see <<transaction-distributing>>). This type of transaction is sometimes used by commercial entities to distribute funds, such as when processing payroll payments to multiple employees.((("", startref="Tover02")))
+Finally, another transaction form that is seen often on the bitcoin ledger is a batched transaction, which distributes one input to multiple outputs representing multiple recipients, a technique called "transaction batching" (see <<transaction-distributing>>). Since this type of transaction is useful for saving in transaction fees, it is commonly used by commercial entities to distribute funds, such as when a company is processing payroll payments to multiple employees or when a bitcoin exchange is processing multiple customers' withdrawals in a single transaction.((("", startref="Tover02")))
 
 [[transaction-distributing]]
 .Transaction distributing funds