As someone who interviewed a lot of engineers, for product engineers I prefer someone with this mindset. Not to say that deep knowledge in the language is bad,

As someone who interviewed a lot of engineers, for product engineers I prefer someone with this mindset. Not to say that deep knowledge in the language is bad, it's just the user and product-focused mindset makes them more effective. They will spend less time bikeshedding on semicolons on pull requests and generally view everything from the lens of "how is this good for the product/user?". Now for tooling, infrastructure, and PL-focused engineers I think caring about the intricacies is important. First, because they'll be doing a lot of meta-programming to build frameworks and libraries. Second, is because to design good languages and frameworks you need to understand the ergonomics of the language and to pick the most intuitive and easy to use features. Finally -- and this may sound like a contradiction to everything I said before -- I think that the best engineers are people who are able to jump between these two mindsets. Be able to bikeshed on the intricacies of frameworks one day and the next day -- when working on product -- to be focused on shipping while ignoring details that they have strong opinions on. A big part of this is dealing with cognitive dissonance. I can have a strong opinion on semicolons in JS but I can jump into a codebase without them and start cranking.