Answer 1

I wouldn't say replacement. However, I never liked Java and I love Kotlin so you know which language is my choice. In addition to running using Java Virtual Machine, Kotlin can be compiled into machine code for embedded or all of the standard operating systems.

Answer 2

That is up to everyone's opinion, fact is that it's another option for Java virtual machine, android and web. It also features interoperability with Java meaning you can use both in same project