All assessments, including the more common entry points, are designed to identify which students are performing at a higher level, compared with other entrants. They can therefore be challenging assessments and the less common entry points are no exception.
An additional consideration is that there are often fewer places available for successful applicants, therefore giving the impression the places are harder to secure. It should be acknowledged however, that there are many more applicants for the more traditional entry points, so chances can be seen as broadly the same.