Attribution models look like measurement. They are not. Every setup encodes a belief about how buying works, and those beliefs are usually invisible to the people arguing about the output.

Last-click says the final touch deserves the credit. Linear says every touch is equal. Neither is true, and both are defensible depending on what you sell.

The useful move is to state the belief out loud before you defend the numbers. Once everyone agrees on the model, the debate becomes about the business rather than the spreadsheet.