Using Exchange ActiveSync with the Android App

Using Exchange ActiveSync with the Android App

My Zoho Mail app on my android device started to behave strangely so I deleted the Zoho App as well as the Exchange ActiveSync account that was set up for it. I reinstalled the app and it started syncing right away and worked flawlessly, without reinstalling or setting up the Exchange ActiveSync account. 

Is the Exchange ActiveSync account no longer required to use the Zoho Mail app?

It's been so long since I originally set up this account that I don't remember why Exchange ActiveSync was used in the first place. What is the purpose of the Exchange ActiveSync account?