GA4
What it is
Google’s free analytics for websites and apps. It records visits and the events you define, and ties them to the channels that brought them.
What it’s good at
Being free and already installed, with years of history sitting in it. The event model treats a site and an app the same way. And it feeds conversions to Google Ads for bidding; that loop is the quiet reason it stays.
What it costs to own
Untouched, it reports fiction: staff traffic mixed in with customers, and every form counted as a conversion, or none. Configuration is a project with an owner: define the events, mark the few that matter, filter your own people out, then set its revenue against the shop system or CRM each quarter; after that, a few hours a month. Skip the owner and nothing visibly breaks; the numbers drift, and meetings keep quoting them.
When it’s a poor fit
It is a poor fit as the single source of truth on revenue. GA4 undercounts by design, so if a board deck quotes GA4 revenue and nobody has set it against finance, the company is steering on an estimate that sits below the real number. It also fits poorly where nobody can say what a conversion means in your setup; then the charts measure a decision no one made.
What it sits beside
Google Tag Manager deploys it and Looker Studio reads from it. The ad platforms will disagree with it, each attributing the same sale under its own rules. The overlap that costs is with finance: the moment GA4 revenue appears beside the audited number, someone has to own the difference.
My experience
I use GA4 to see which way things are moving, and take the final number from the finance system.