Reporting a scam site is a good idea but it does no good if the reports aren't acknowledge properly.
The main point is, regardless if the potential effect is only small, it only takes a minute to report anyway. And that minute, from multiple people, can potentially save a few people from losing money.
How many reports are needed for a scam site to be taken down ?
If we report a site, what are the chances that it will be taken down ?
No one knows for sure, but report anyway even though we don't have the answer to this. It does make a difference, we just don't know how much.