First, it should be stated that profiling is a very controverisal issue and should be dealt with in the most sensitive way. Second, I believe as the world gets smaller through globalization and as the world becomes more complex, profiling will be less and less applicable and therefore may be a thing of the past. The basic premise of profiling is that certain types of people are more apt to commit certain crimes. This is being challenged now and in time, I suspect, will hold no validity. For example, what does a religious fundamentalist look like? You can't really tell anymore. What does a criminal look like? This is hard to say. Consider Bernard Madoff.
Offender profiling is helpful to the extent that we accept that future crimes are based off of past ones. If this premise is accepted, than acting on created profiles are very useful. However, I think any law enforcement agent would argue that profiling is one of many tools that are utilized in order to find those who have broken the law. Profiling cannot take the place of strong investigation techniques, meticulous analysis of physical evidence, and substantiated testimony. In the final analysis, profiling can be a guideline and a very good predictive element, but it cannot provide all of the answers because crime happens in "real time" and is not purely an exercise of the past. While it can be a helpful tool, it is one of many.
Since you are asking specifically for usefulness, I will drop my cons about profiling and focus on how it could help.
One useful thing about profiling is the use of patterns. When a killer or rapist strikes, it is good to know who they attack. When we profile,we are able to see behavioral patterns in the attacker, which allows us to warn potential victims.
Another useful thing is that it helps us understand the background of the offender. If we notice a certain pattern in background, upbringing, socioeconomic status, or literacy level, we can become more aware of how those backgrounds are either enabeling or making it easier for offenders to become what they are.Hey, it could even help our parenting skills, for all we know. Serial, homosexual killer and rapist Jeffrey Dahmer, for example, was brought up by what we could call "sensible, Christian, and decent" parents: But what else went on in there? Do we know for SURE?
And my final benefit for profiling is predictability. Surely, we can make mistakes but when lives are at stake, it is best to take every measure possible to avoid a future strike. When the 1970's saw a pattern of brown-haired white girls getting raped and killed, they were able to see what some rapists were looking for, and some were caught- thought not all (hence, the story "The Lovely Bones") Yet, the crimes were so new that there was a lack of predictability as to how the next victim would die. A bit of profiling could've helped on that one big time as well.
Offender profiling is clearly helpful at times, but it is in no way a panacea.
Offender profiling can be very useful when investigating such things as serial killers or other types of crime like that whose perpetrators are easily profiled.
On the other hand, many types of crime are not really linked to any one kind of person. In addition, profiling can actually cause problems and impede investigations. When the person who actually commits the crime does not fit the profile, time is wasted searching for a person who does fit the typical profile.