AASB 138 describes the distinction between the treatment of internally generated goodwill and purchased goodwill (as well as other intangibles) as arising because:choose suitable one

the two different sources of goodwill result in two different types of asset

.internally generated goodwill is developed in order to be sold, so its value will be recognised at that time

.internally generated goodwill cannot be reliably measured.

recording purchased goodwill could lead to the manipulation of profit and asset amounts.