Put differently, if you could turn back the clock or re-write the Fifth Amendment to the US Constitution, would you take out the right against self-incrimination? If you care about truth, or about the victims of crime, the answer has to be YES, right? Here is an extended critique of the constitutional right against self-incrimination by Bennet Haselton, who makes a provocative though persuasive case against allowing criminal suspects to plead the Fifth and answers every possible objection you may have …
prior probability 
If we didn’t have the Fifth Amendment would the criminals tell the truth anyways?
Fair point … in fact, I suspect that most criminal defendants would definitely tell a bunch of lies !!! But at least their testimony would provide jurors new information to allow them to update their “Bayesian priors” about the suspect’s guilt or innocence