Depending on which solution you use; some of them are just a few KB, which is not so much. Doing log-analysis has its own drawbacks: not everyone has access to

Depending on which solution you use; some of them are just a few KB, which is not so much. Doing log-analysis has its own drawbacks: not everyone has access to them, bot traffic will be a lot higher, and certain information is hard to access (like screen size). You can't always "just" use it.