What can make scala more popular?

Actually the variable is immutable. It is just initialized outside a constructor.

There are many others things that sure me that concept is unfriendly. It doesn’t not solve tasks. it tries to restrict use case.

I doesn’t have qualification to argue. Actually I do not understand it.
I can’t understand motivation for such dead simplicity.
I can’t understand simplicity.
But I am sure simple restrictions by virtual rules doesn’t make a language popular.