Apart from possible tracking snafus, this can be valuable in determining what type of promos your particular type of traffic likes to see.
Do these places have different types of promos?
How do the promos match up with your keywords?
Whereby you don’t want to stop analysis with clicks, but extend to player quality they produce for you.
What is the player value resulting from each promo?
That’s the actual bottom line.
Just because a particular program decides that for itself a certain type promo brings certain results, it doesn’t mean it holds true for your traffic.