Open Is Better?

It certainly isn’t any more secure:

Automatically updating Android apps could get riskier thanks to a change Google developers have made to the way the OS discloses new app permissions, such as the ability to send potentially costly text messages or track a user’s precise geographic location.

Previously, automatically updated apps displayed explicit details when a new version gained additional privileges. For example, an app that previously tracked only coarse GPS coordinates would warn users if an update would begin receiving fine coordinates. Similarly, a newly assigned ability to send SMS messages would also be disclosed. Under changes implemented through the latest Play store app, neither new privilege is displayed if a user has previously accepted any other permission in the same category as the new permission. In other words, by accepting one permission from a category, users agree that every other permission in that category can be added without notification in future updates.[Emphasis added]

Remember, you aren’t Google’s customer. You are Google’s product.