There are some folk that can't learn the skills in these topics but can recall questions and answers so for them this is the only way for them to pass these exams.
What happens next is they land a job but can't perform since they are now in the real world. I used to think such sites to be terrible but now think that anyone foolish enough to use such gets what they deserve later.
I would recommend to not use any Dumps. Just learn the concepts well and attempt to crack the online test using your learned skills. Hands-on experience beats all the dumps and guides out there any day