There are soooooo many 
Here are two because they are fresh in my mind as @pragdave talks about them in his online course.
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It’s incredibly easy to build your apps as a series of components and microservices.
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One of the reasons Elixir code is more maintainable, readable and easy to make sense of is because you don’t rely on endless if/else statements. So whereas traditionally (say in an OO language) you could have a method with several different outcomes depending on the number of if/elses (and nested if/elses) which can be a nightmare to traverse, in Elixir you can simply use pattern matching with multiple method definitions so each function really only has a single responsibility. This makes it incredibly easy to refactor or extend your code.
There are loads more too, check out some of these threads:
https://elixirforum.com/t/what-do-you-think-are-the-most-appealing-aspects-of-elixir/2440
https://elixirforum.com/t/if-elixir-were-an-animal-what-would-it-be/2353
https://elixirforum.com/t/why-elixir-slides-from-my-elixir-presentation/2431
