Meta-heuristics are particularly suited for combinatorial optimization problems, given that, although they are not usually guaranteed to find the optimal global solution, they can often find a sufficiently good solution in a decent amount of time. So, they are an alternative to exhaustive search, which would take exponential time. For example, ant colony optimization algorithms have been used to approximately (or exactly, in the case of small or medium-size instances) solve the travelling salesman problem, whose decision version is an NP-complete problem (which means that, unless P=NP, there is no polynomial-time solution to solve it).
Meta-heuristics can also be easily applied to many problems, given that they are not problem-specific. For example, in the case of genetic algorithms, you just need to encode the possible solutions, but, in principle, you can apply genetic algorithms to a wide range of problems, although they may not always be the best solution to each of these problems. Moreover, as opposed to gradient-based optimisation algorithms, there's no need for the gradient of the objective function. For instance, in the case of genetic algorithms, you just need a way of evaluating the solutions (e.g. the fitness or the novelty).
Meta-heuristics often incorporate some form of randomness in order to escape from local minima. Ant-colony optimization algorithms or simulated annealing are two good examples of this approach.
If you are still interested in meta-heuristics, the book Clever Algorithms: Nature-Inspired Programming Recipes (by Jason Brownlee) is a very good resource for learning about them. There's also a Github repository with the implementation of the algorithms described in this book.
