Phonetics is a theoretical and experimental linguistic discipline. Its knowledge in its different branches has several applications in every day of our life in society: (1) in the phonetic correction so much of the own language as in the process of acquisition of other languages, always with a didactic use; (2) in the evaluation and rehabilitation of speech and hearing dysfunctions, in an application that connects with the clinical and logopedic practice; (3) in Linguistic Engineering through the synthesis and the automatic recognition; and (4) in the environment of the Justice since the analyses of Forensic Phonetics are an important test in many judicial processes. All the exposed arguments prove that Phonetics is useful and the critics that some researchers demonstrate toward this discipline is totally unjustified.