I'd say it's worth it to the mid or long term, so you'd benefit from CL's strengths and advantages. It's more difficult than mainstream languages to start a web app only because there are less material, project templates or full blown frameworks to get started, so you better know the web already. In addition to the awesome-cl list of libraries, I recommend to check out the Cookbook https://lispcookbook.github.io/cl-cookbook/web.html to grok the different parts of a lisp (web) app.