It may be more efficient and safer to solve a particular system of equations using the addition method.
You could save time and
If the systems look like they can be added/subtracted directly or with a simple multiplication of one of the equations, the addition method will solve the problem quickly.
When the substitution method is employed, it may result in odd fractions or many negative multipliers, which for most of us are
Containing awkward fractions or too many negative multiplications.