There may also be times when there is sufficient evidence to secure a conviction, yet the circumstances of your case may prompt authorities to provide you with a second chance.
It is important to draw a distinction between having a case dismissed and being acquitted. When you are acquitted, you are prosecuted and found to be not guilty. In such a case, the state cannot retry you on the same charge. When a case is dismissed, the state can choose to reopen its prosecution in the future (unless the case is dismissed with prejudice).
You might question the need to have your public record expunged if the charges against you are dismissed. An expungement in this case would eliminate any trace of your potential involvement in criminal activity (including the record of your arrest).
Related Posts: Campaign pushes for expungement process overhaul, 2018 bills facilitate some expungements, Looking at the expungement process, Who can get an expungement?