It looks like you're using JavaFX for ReportMill, which is plenty modern enough in terms of capabilities and API.
Web or not web probably won't have a particularly big impact on your apps. Given that they're developer tools and those are normally client side apps anyway, it doesn't seem likely that this is the determining factor in whether or not to use them.
Revamping your website would likely be a better use of time! It looks like you made it in 1998 and haven't updated it since, for example, it only fills one quarter of the screen on my display. The screenshots are tiny and low res. The app itself is using the slightly dated default JavaFX theme - why not just spend some time on your JavaFX CSS, website and examples, and give them a fresh lick of paint?