Do I need a Google Merchant Account if if implement Unity Ads in my game?

I’m planning on releasing a game for free but the game will have video interstitial from Unity Ads. I’ve already created my Unity Ads account and paid for the Google Play Developer license. Is the Google Merchant Account really necessary? Won’t my Unity Ads account take care of the revenue?

I don’t think so… because you will get paid by unity not by google…