So what are they for?
The straight hemostat is the key ingredient that allows for this form of bris to take place. Its job is to grab the foreskin and the membrane beneath it at the same time so the circumcision can take place in one-step.
|Blunt edged scissors|
The bent hemostat and the blunt scissors are sometimes used, to remove the "tzitzin ha'm'akvin" - the extra membrane, or the inexact skin that may have resulted from the bris. This is not specifically the mohel's fault or the result of a job poorly-done, as much as it is just the circumstances and the reality. (Sometimes it might be the mohel's fault, but he is taking the opportunity to fix it in a manner that he can). Why blunt? So it doesn't poke or stab the baby - our goal is foreskin and membrane removal, nothing more.
Remember that the mohel's job is to produce an as-beautiful-as-possible circumcision. And he does not have the benefit of the privacy of the operating room to do that. This is why some cases produce the need for the two-step process, which is probably better presented as "making things pretty."
Simply put, these are primarily the back-up instruments the mohel carries in his bag-of-tricks, which come in handy sometimes or often.
Of course, there are mohels who will claim to never use them. They are either VERY expert mohels, or they are not sharing everything about themselves. :)