Short answer: Yes
Long answer: You are not going to always work on simple front end projects only in your professional life. There will be stuff/tasks that can be done more easily (or must require) using frameworks/libraries like React/AngularJs, Vuejs etc There maybe even times you need to implement your own utilities or JS plug-ins for your employer or needs. This means you must have good knowledge of JavaScript.
At the same time, as a web developer, our job is to provide right solution at right time using right technology, if you or your team feels JQuery is good for the specific task, use it. But again, to develop/debug any little advance applications or front end you will require good knowledge of JavaScript.
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