SUMMARY This option will be valuable in software that already make use of mouse right-click like Firefox+Gesturefy addon, Virtualbox, CAD software, DoubleCommander, probably some painting apps... Furthermore, the same button will break mouse gesture provided by the application (e.g. Firefox+Gesturefy). The idea is, like in other gesture-recognition software, to have a list of applications for which instead of the default button, gesture event will be triggered with alternative one. ADDITIONAL INFORMATION FYI: Easystroke is not maintained any more and is not usable in Wayland session, so we only rely on Plasma =).BTW, it also breaks Meta key ability to open the 'Applications launcher' on X11.
As announced in https://pointieststick.com/2023/07/26/what-we-plan-to-remove-in-plasma-6/ and https://community.kde.org/Plasma/Plasma_6#Removals, I'm afraid KHotKeys has reached end-of-life in Plasma 6. Accordingly, all bug reports and feature requests for it must be closed now. Most of what KHotKeys could do can already be done with the newer KGlobalAccel system in Plasma 6. A few features such as mouse gestures and triggering conditions based on changes to window states are not yet implemented in the new system. These will be added in the future if and when resources materialize for them, and/or when a kind soul submits patches to implement them! :) Meanwhile, the 3rd-party "Mouse Actions" app (https://github.com/jersou/mouse-actions) may be usable for implementing your own mouse gestures again. Thanks for your understanding, everyone.