What I check before calling a button click a conversion.
Track the event, understand the action
A GA4 event tells you that a defined action was recorded. It does not automatically tell you that the business received a genuine enquiry. For example, tapping a telephone link may be counted even if the visitor never completes the call.
A form-submit event can also be misleading if it fires on button click rather than a verified success state. I want to know exactly when the tag triggers before I use the number in a client update.
How I approach validation
Start by writing down what each event name means. Test the page on a real phone and a desktop. Check whether an event fires twice, whether it works on an error state, and whether the event reaches the correct analytics property.
Where possible, compare events with form delivery or call records. Analytics tells one part of the story; operational records can confirm another.
My take
I think measurement is a quality-control problem. If a dashboard cannot explain what actually happened, the fix is not another dashboard. It is a clearer definition and better instrumentation.