If you read the original report, it says that it basically just displays a fake banking login page. It also says that it requested accessibility service permissions, which makes me think maybe it brought up the fake login pages "in the right moment" (as in as users opened their banking apps) to make it more convincing, even though the article doesn't specify that.

Either way, IMO the problem here is clearly with the Play Store allowing this app in, and not with Android's security itself. These apps are misusing the accessibility service system, which is obviously necessary for a ton of important use cases (and of course also requires the user to grant very explicit permission). The fact that the accessibility services are a thing doesn't delegitimize Android's security improvements over the years.