The problems in general analytics
General analytics like Google Analytics, Mixpanel, Optimizely, and Amplitude are incredibly flexible tools, providing hundreds of different perspectives to the behavior of your visitors and users.
However, what matters for most businesses is not all the myriad of metrics, but to understand how their product can raise interest, desire, and finally traction as a result:
This document explains why standard analytics fails to understand this classic conversion funnel and why a more task-oriented tool is needed.
Due to above problems your conversion funnel looks like this:
Mainly your decisions are based on severely limited knowledge about how the visitors convert. Moreover, the wins are likely temporary: what works on the current time range, doesn't necessarily work in the future.
You can experience this yourself with a simple A/A test with two identical variations. The results vary for months, even with a high-traffic site. *
Many businesses would be better off if they didn't run A/B tests at all.
Author of "Design for Hackers"