To me and, I suspect, to most people today, the necessary and proper clause (also known as the elastic clause) makes a great deal of sense. I cannot imagine how things would be if it were not in the Constitution and if the Supreme Court had not ruled that it really meant something (McCulloch v. Maryland).
The enumerated powers that are in Article I, Section 8 do not cover all that many things. They were written, after all, over 200 years ago. They could not possibly have foreseen all the things that Congress might have to do. Therefore, I think the clause was absolutely necessary because it allowed Congress to have more expansive powers to deal with issues that have come up in the years since the Constitution was written.
At the time that the Constitution was developed no one could have foreseen the many changes, inventions, and dynamics that the future would hold. Section eight allows for the members of Congress to use funding to provide for homeland security. When one looks at the situations that our nation has faced and the need for homeland security and war past and present, it is easy to understand why the section was developed.
War and security cost an enormous amount of money. General operation of a country is costly. The government could not run like a church by being dependent upon donations. It was necessary to set up a system of public funding.
The other rights given to Congress account for the many unseen issues that may arise. Since technology and science have advanced at such a rapid pace, Congress has not always been able to keep up with laws that address the issues that arise. However, because of section 8 Congress has the power to determine the use of weapons of mass destruction and to control others from using weapons carelessly.