Here you will find some screenshots of some of today's web applications built in CL: http://lisp-screenshots.org/ and here an opinionated tutorial: https://web-apps-in-lisp.github.io/ One example: ScreenShotBot https://screenshotbot.io/ a successful open-source product and company. It now replaced Facebook's automatic screenshot testing tool (source: their blog). So, web apps in Lisp are possible -with a right amount of learning time and elbow grease.
The incremental development and interactive top-level are still precious and unmatched.