Initially at least, your report will not be viewed by a human but a computer, this is why it is very important to select the correct report. For example, if someone was impersonating you on Facebook and you reported the account for being abusive/threatening, the computer will start to look for abusive/threatening language on the page. It is very possible someone can make you feel abused/threatened by creating an account in your likeness but without posting anything objectively abusive or threatening. So, when the computer can’t find what you have told it to look for, it will say “no violation”.
If instead the account is reported as an impersonation, from the account it is impersonating, you are asking the computer to look for something completely different. The computer will scan both profiles and see: yes these two pages are using the same/similar images, this account has been active for 5 years and this one has been active for 5 days, this account seems to have posted fairly sporadically for 5 years, whereas this one has posted 5 statuses in the last hour. By selecting the correct report the computer knows what to look for and can therefore work much more effectively, here this would by now be enough evidence for the Facebook impersonation algorithm to agree with you and remove the impersonation account.