What Is Ads Test Mode?

In the documentation, in the ads it says ‘always use test mode for testing’, and I was wondering why?
i mean i will use it, but is it that important? what does it do?
I Am developing a game and am planning to release it for android and I don’t know what it means…

The admod behavior is for exported games for Google Play and Apple App stores,
and you will need a google admod account to use it.

Test mode it to test the game without using the actual ads.
Not using the test mode could lead to spamming real ads, and is against admod regulations.

Test mode is an AdMob feature, when you get ready to start using AdMob, you should read over their documentation which will explain all that: https://developers.google.com/admob/android/test-ads

The reason it’s important is that Google may ban your account if you test with real ads enabled, because that is considered fraud.