(a) a larger angle to be subtended by the object at the eye and hence viewed in greater detail.
(b) the formation of a virtual erect image.
The object to be viewed can be brought closer to the eye than the standard near the point when using a magnifying glass. As a result, the item near the eye can subtend a bigger angle and so be perceived in greater detail. There is also the construction of a virtual erect and expanded image.