Good great is a good indicator, but is no guarantee of a good tenant. Good credit history indicates that someone pays bills on time and knows how to manage their finances. Renters usually have worse credit than homeowners / landlords. Bad credit is not an absolute disqualifier. There are perfectly valid reasons why some people have bad credit and some of those people with bad credit can be outstanding tenants.
A credit history check is not the beginning or end but it is a good place to start to get a picture of whom you're dealing with.