Can Python be as great as Java for Android applications?

Answer 1

no.

Answer 2

As great as Java - no
Sufficient - mostly
Reasonable - why?

Answer 3

No, not even close. Android was created completely based on Java and Java libraries. Well, now you can create an android app using anything (IONIC, C++ Libs, etc), but many veterans of Android Development will surely tell you how they created their best apps using Vanilla Android environment. Even before Android Studio and all those new frameworks, programmers were creating awesome apps with just a text editor and android sdk. Moreover, python is excruciatingly slow for big apps such as games; python frameworks and libs are much more suited to provide backend capabilities for your apps.
But, well it all depends on your requirements and how your app is going to work, so forget about what language is best for your app, and design and implement your app as according to your requirements.