Rigor is relative
How much measurement a business needs depends on the business. The same test can be essential or a waste of money.
Testing should be rooted in three things: the scientific method, the brand’s own traits, and platform dynamics. Clear hypotheses, measurable goals and rigorous execution are non-negotiable. How elaborate the apparatus should be is not.
A business doing $10M a year through a single sales channel needs a different approach than one doing $100M across several. Incrementality testing might be unnecessarily complex and costly for the first and essential for the second.
Platform behavior moves the same way — changes to auction dynamics and ad delivery quietly rewrite which levers matter. The point is to experiment in order to unlock growth, not to test for testing’s sake.