What is the advantage of representing a data in Variance -Covariance matrix form?

What is the advantage of representing a data in Variance -Covariance matrix form?

[Harsha Medikonda]

Where are you using the variance-covariance matrix? Are you working on Non-Linear Regression?

[charles alexander]

it is a matrix that is distributive; a(bk)=ab(k).

it reduces the matrix to an equivalent cofactors to determine the associated elements.