Why Is The Maximum Likelihood Estimation (MLE) Method Taken as the Benchmark for Comparing with Other Methods?
There are 3 major reasons in my opinion which makes the Maximum Likelihood Estimator so popular:


Intuition
It is very clear what's the logic behind this method and what you maximize. It makes sense even if you have little knowledge in probability and statistics.
Properties
It has great properties (Some are only asymptotically, namely with many samples) such as consistency and efficiency. This means it always makes some sense to use it. 
Easy to Derive
It is usually pretty easy to derive the optimization problem defined by the MLE and in some cases it is also simple to solve it.


Now, many parameter estimation methods are compared to the properties of the MLE - Efficiency and Consistency.
If they exhibit similar performance than they are as optimal as the MLE.
Otherwise, they are not, as expected.