introduction :

i think it can be used by hackers as it will show those things of the website which weren't mean to be seen . but what i think is we can test our websites out for vulnerability . it will help allot in finding sensitive informations on that particular website .

it gives you 40 free credit for the testing . having two options of scanning light scan and full scan .

This is a discovery activity which allows you to discover resources that were not meant to be publicly accessible (ex. /backups, /index.php.old, /archive.tgz, /source_code.zip, etc).
Since 'security by obscurity' is not a good practice, you can often find sensitive information in the hidden locations identified by the URL Fuzzer.