Most likely in such companies you would have a separate devops team, separate sre team and so on. How can you use the skill if it's completely separate set of responsibilities managed by other teams?

The only way to give impact in this area is to pivot from writing code to managing infrastructure (i.e. writing code in yaml, pun intended). So, back to the question, what is the point to learn kubernetes above basic acquaintance?

You can use this time to pursue other endeavours like prepare talk to the conference, learn the tools better which you use every day, automate some of your daily workflow (i.e. explore your code editor, write extension to your code editor to automate some actions and so on). This activities will yield better results in my opinion and you'll use this knowledge everyday instead of deep diving into kubernetes without actual opportunity to keep your skill up to date on long distance without going full into devops and becoming less competitive in your main trade.