Hi Erik,
Thank you for bringing your question to us. The lite version can be used if your app is distributed through Google Play Store as described here -
https://developers.google.com/admob/android/lite-sdk because the Google Play services APK already has our Mobile Ads SDK in it. Otherwise, there's no guarantee that the Google Play services APK is installed on a device.
Kind regards,
Aryeh Baker
Mobile Ads SDK Team

ref:_00D1U1174p._5004Q219eBC:ref