We highly recommend you update your tracking parameters to get the most out of our platform. If you do not update your campaign tracking settings:
It will impact the accuracy of your dashboard results and insights of campaign-level granularity. Channel level granularity won't be affected.
You can still run a lift test without setting the tracking parameter, but we would suggest updating the tracking parameter together with lift test as Lift test will trigger the re-learning phase.
Updating UTM parameters in your ads can have different effects depending on the advertising platform you're using.