When Google Analytics and Google Ads are linked, Google Ads can use conversion events from Google Analytics to optimize your bids for better ad placements and performance.

Core idea in simple terms

Once the accounts are linked and GA4 “key events” are imported as conversions into Google Ads, those conversions become optimization signals for Smart Bidding strategies (like Target CPA, Target ROAS, Maximize Conversions). Google Ads then adjusts bids in real time to favor clicks and audiences that are more likely to perform those conversion actions you defined in Analytics.

How Google Ads actually uses GA conversions

  1. You define events and key events in GA4
    • In GA4, you track user actions such as purchases, lead form submissions, or sign‑ups as events and then mark the most important ones as key events (conversions).
 * These key events represent the outcomes you care about (e.g., “purchase”, “generate_lead”).
  1. You import / create conversions in Google Ads from GA4
    • Through the shared interface, you choose which GA4 key events should become Google Ads conversion actions.
 * After setup, the same conversion data flows into both GA and Google Ads so you see consistent numbers across platforms.
  1. Google Ads uses those conversions for Smart Bidding
    • Smart Bidding models learn which queries, audiences, devices, times, and placements lead to GA4 conversions and then automatically increase or decrease bids to hit your goals.
 * For example, if a certain audience segment converts more often (based on GA4 data), Google Ads may bid more aggressively for them and less for low‑value traffic.
  1. Conversion counting and attribution details still matter
    • When you import a GA4 key event as a Google Ads conversion, you choose settings like “One” vs “Every” conversion, which controls how many conversions are counted per ad click.
 * GA4 may show multiple key event counts for the same user, while Google Ads reporting can show one or many conversions depending on your configuration.

What this looks like in practice (short story style)

Imagine you run an online course site and track a GA4 event called course_purchase that you mark as a key event. You link GA4 with Google Ads, import course_purchase as a primary conversion, and set a Target CPA bidding strategy.

Over time, Google Ads learns that users on mobile in the evening who search “advanced python course online” and come from certain locations are more likely to trigger course_purchase. The system then automatically bids higher for those auctions and lowers bids where conversions are rare, effectively concentrating your ad spend where GA4‑tracked conversions are most common.

Key benefits of using GA4 conversions in Google Ads

  • Better bid optimization
    • Main benefit: Google Ads uses GA4 conversion data to optimize your bids for ad placements that drive more valuable actions.
  • Consistent measurement
    • You measure the same conversions in both GA and Google Ads, so reporting lines up and analysis is easier.
  • Deeper funnel signals
    • GA4 can track site/app behavior beyond just the final purchase (scroll depth, engaged sessions, micro‑conversions), and some of these events can be elevated to key events and then used as optimization signals.

Direct answer to the exam‑style question

When Google Analytics and Google Ads are linked, Google Ads can use conversion events from Google Analytics to optimize your bids for ad placements , improving performance by automatically focusing spend on traffic most likely to convert.

TL;DR:
Link GA4 and Google Ads → mark important actions as GA4 key events → import them as Google Ads conversions → Smart Bidding uses them to automatically optimize bids and placements for more and better conversions.

Information gathered from public forums or data available on the internet and portrayed here.