Not everyone can pay for a reliable arrest warrant search so they all end up using a free search for warrants. While this is beneficial because they dont have to pay anything, they will have to watch out for websites that can take advantage of them and scam them of their money.
Having access to websites that can offer a free search for warrants of arrests is a good thing for people who are suspicious of the people around them. In making a thorough search about them, they get to find out if the person they hang around with is safe. If the person happens to have a criminal record and a valid arrest warrant, you can easily report them to the police.
Unfortunately, not all searches are free. You need to be careful where to do your search so you dont mistakenly accuse someone of an issue that has already been settled.