> you will obviously know if a campaign has been "effective", if sales increase.
This is simplifying marketing too much. You’re likely to run concurrent campaigns on different platform, Facebook, Instagram, Google Search, Twitter, etc.
Marketers would like to understand what campaigns and what medium helps drive sales/installs. No need to waste money on Twitter ads if it turns out no one actually ends up buying.
This is easily managed by changing the url based on the source of traffic (e.g., the omnipresent ?camId=foo on so many links). Heck, back when I published a magazine, I did this in analog form by using slightly different addresses for mailed in subscriptions (adding a Dept S to the address for the ad in Step by Step, Dept H for How Magazine). It doesn't take intrusive user tracking to be able to measure this sort of thing.
There are no URLs in app installs. The ad links to the iOS app store, and Apple does not give you any information post install on where the source came from.
Most ads don't link directly to the app store, but instead send you through a tracker site which logs the click before forwarding you to the app store.
This is simplifying marketing too much. You’re likely to run concurrent campaigns on different platform, Facebook, Instagram, Google Search, Twitter, etc.
Marketers would like to understand what campaigns and what medium helps drive sales/installs. No need to waste money on Twitter ads if it turns out no one actually ends up buying.