As per my experience, its definitely worth learning and acquiring hands-on skills on the popular cloud platforms. AWS, being the front runner, becomes the viable choice.
Now, lets suppose, at present, you are not dealing with any cloud. You are a developer working on on-premise systems. As you gain experience in your career, apart from doing coding in 1 or 2 languages, you will be required to provide technical solutions from multiple perspectives like, solution architecture, choice of technology, high availability, big data set-ups, scripting tools etc. A data engineer will be supposed to play the role of a technical architect or a solution architect one day or another as he moves up into senior roles, given that he wants to stick to technical ladder.
Same is the case, when you are building data solutions on cloud. You will need to learn atleast the know-how of multiple AWS services so that you can provide an end-to-end technical solution of the problem at hand.Don’t get intimidated by the names various AWS services. They are easy to get started and you definitely can not equate it to same as learning different languages. Its about understanding the problem and different aspects of it and mapping those different aspects into a solution using the services at hand.