What is the benefit of using a shortcut in a reaction between two chemicals ?

To yield more output

Explanation:

The shortcuts in a chemical reaction are used to yield the final output by following a short route rather than the chemically defined long process of production thereby yielding final chemical product in higher amount as the production would become faster.

For example –  

If the chemical process in photorespiration is replaced with shortcuts, the chemical products can be recycled very easily at one location instead of following the natural path of processing.  

thermophiles, notice the prefix thermo.

his research revealed two genetically different groups of prokaryotes, which justified splitting kingdom monera into two kingdoms. the genetic and cellular differences were so great, that these two kingdoms were eventually placed into different domains in the current three-domain system.