In my experience... (Score 1)

As a guy that manages web developers... In the last 10 years front end software development has gotten really complex. Gulp, Grunt, Sass, 35+ different mobile device screen sizes and 15 major browsers to code for, has made the front end skillset very valuable. And yes, one slip up on the front end can cripple conversion rates and costs 10's of thousands of dollars per hour. Or worse poor design and testing can create hard to find errors that cripple production invisibly. On a web product that has been completed and released to production, probably 70% of my allocated resources are tweaking front-end pages and setting up A/B tests. As a developer if you have ignored client side programming and the front end stack, you are doing yourself and your resume a disservice. I would recommend "Javascript:Understanding the weird parts" on Udemy for a refresher.