What is the use of Transaction Code?

As it relates to Accounting Entry Template (AET), a transaction code is required so that the AETs can be configured for every possible transaction code combination.

But, is it correct to say transaction codes are only needed/relevant for the retirement of assets and recording of lease assets that will transfer ownership from lessor to lessee when the lease expires? Also, for reporting if I want to report on assets based on transaction codes?

My understanding is, selecting or allowing the system to automatically default the transaction code during an asset retirement allows the system to use the AET that has the Accounting Entries that will create accounting entries according to the disposal code selected. Also, selecting an AET with a transition code of S or R does not make a difference because the same Accounting Entry Types are on both AET with transaction codes S or R. The difference is how gain or loss is calculated based on which disposal code is selected. For example, gain or loss is calculated