Question: I am curious to know why should a Database person learn LINQ. How can it be useful.

Answer: 
Linq provides "first class" access to your data. Meaning that your queries are now part of the programming language.

Linq provides a common way to access data objects of all kinds. For example, the same syntax that is used to access your database queries can also be used to access lists, arrays, and XML files.

Learning Linq will provide you with a deeper understanding of the programming language. Linq was the driver for all sorts of language innovations, such as extension methods, anonymous types, lambda expressions, expression trees, type inference, and object initializers.
I think one of the many reasons why one could consider linq it because linq is big productivity boost and huge time saver