The reason you can be tried as an adult is because you are old enough to supposedly know better than to commit the crime.
The reason you can't rent apartments, hotels, etc. is because you are not yet old enough to legally enter into contracts. i think that in most of the U.S. you have to be at least 18 years old in order to enter into a contract.
woah littlemissitaly very good question I, in not being a lawmaker, do not have. Although, fair to state, if a person is tried as an adult at the age of 17 and found not guilty they should immediately be given the opportunities that are available to an adult at the age of 18.
so yes, in my opinion, in considering a legal system, it is most likely to teach or cause responsibility for ones decisions or actions........upon doing so someone will most likely possess the level of responsibility needed TO uphold a legal and binding contract.