Google Analytics matters because launches need evidence about visitors, pages, conversions, and campaigns. It gives builders a precise word for the thing they are changing, debugging, reviewing, or shipping.
ELI5
Think of Google Analytics as a proof or operations tool for the live product. It gives one small job a clear name so the whole app is easier to understand.
In practice
Use it when launch, analytics, revenue, reliability, or production proof matters. In practice, name the owner, input, output, failure mode, and proof before relying on Google Analytics.