short cut joins are used to improve the query performance at universe level.
Suppose if we have 4 tables A,B,C and D

A--->B---->C---->D and  there is a chance to link A--->D  but we should not link (causes loop) and we need data from the tables A and D then it will get the data in the path A--->B---->C---->D , it consumes lot of time and resources.

In this case instead of linking A---->D using normal join we should link A and D by using short cut join and this will not create any loop and get the data in the path 
 A--->D, it consumes less time and resources.