It also became a defensive weapon against society and the laws and proceedings that often took place, in that it allowed a person to insist that they did not have to and were not going to answer a particular question that was asked of them, and what was more, they did not have to answer the question because they were protected under the law. Somewhere along the way, though, this protection that was designed for a very specific purpose began to be extended to other purposes, therefore 'watering down' the importance of the 5th amendment and making it into somewhat of a joke as opposed to a serious legal matter that can and should only be used in the most serious of circumstances in criminal cases where one person is testifying against others and self-incrimination is a real possibility.

In the original cases where this amendment was invoked,...

By using this amendment, they basically incriminate themselves anyway, but this is not the point. The main point of the 5th amendment is that it was designed to be for criminal cases and now has moved on to many other areas where its use is questionable at best.
Bibliography

Bart v. United States. 349 U.S. 219 (1954).

Counselman v. Hitchcock. 142 U.S. 547 (1891).

Emspak v. United States. 349 U.S. 190 (1954).

Mapp v. Ohio. 367 U.S. 643; 81 S. Ct. 1684; 6 L.Ed.2d 1081 (1961).

Quinn v. United States. 349 U.S. 155 (1954).