ReadInt

Why use this command?
It always gives strange results (probably because of extraneous 'header' bytes or control codes (i.e. Carriage Returns etc.) in text files or something.
ReadLine can be used to read numerical values (floats too!)
So what is the point of ReadInt?

I am guessing it's more useful for reading from data streams rather than files perhaps but could someone please clarify this for me?

Yes. You would also use it if you've created a custom file format using "WriteInt" or perhaps if you're reading binary files (though in that case it would probably be ReadByte).