National criminal/eviction checks

[Bienes Raices]

I've been looking at another site (sorry Josh :oops: ) and some experienced people on there were commenting that nationwide eviction/criminal checks are "useless" and "for idiots." I have learned how to do criminal at the county level for free on the internet. However I was wondering what others opinions of the national checks are, and if there is a problem with them, what is the issue?