Question

Is there a situation where the use of the lambda expression is particularly helpful or its mainly usage is to write less code?

Answer 1

The justification for adding lambdas to the language was two things.

(1) They make syntactic transformation of query comprehensions possible. When you say

from customer in customers 
where customer.City == "London" 
select customer

That becomes

customers.Where(customer=>customer.City == "London")

(2) They can be turned into expression trees, and thereby make LINQ-to-SQL, LINQ-to-Entities, and so on, possible. That is, they can represent both the ability to do their semantics and the ability to inspect their structure.