I don't believe Justin has anything against web apps it is just the development environment which has some real issues. Delivering an app via the web is a great idea and has many benefits as you rightly say. However when you are delivering an app to a client that integrates with a database containing personal, financial or otherwise confidential information then you absolutely need to know that it is robust, secure and that transactions are handled correctly.
Look at the debacle with the recent NHS junior doctor website where a lot or personal information became available to all users of the system. Nobody is saying don't do web apps, that would be a backward step. However, web development currently needs to be done very, very carefully to avoid these kinds of situation. There doesn't appear to be either the framework or the tools that make this job easy and a casual approach to web app development can lead to, at best a crappy application which dissapoints users, but at worst a serious impact on a business's reputation and financial performance.
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