If you have the resources, you should follow the guidelines for whichever platform the app is on.
In the past many companies considered iOS to be 'the market' and only made Android apps as an afterthought. As a result, they often simply built an iOS app in Android to save them time and cost. This wasn't done because it was a better way of doing it, just a faster way.
As a heavy Apple user, this is a grudging admission.