Genetic algorithms(GAs): to be considered only as optimization algorithms? Are GAs used in machine learning any way?
Yes, as you found they (evolutionary algorithms such as genetic algorithms) are using for optimization tasks. One reason that they are not using mostly in machine learning could be their performance to converge to the optimum point. Also, implementation of the GAs for some domains could be problematic and it could not be generalized like gradient descent, as it's involved in at least 5 phases‌ (mutation, crossover,  ...).