In some KDE apps there is not a consistency between whethever to show Move to Trash, Delete or both buttons. I would like to suggest a global standard: Only Move to Trash would be shown, and Delete would only be shown if the user is holding the Shift button. If not possible (for example, if Shift does something in the app so it could cause conflicts), then we show both options by default. Examples of inconsistencies: Gwenview, Kate, Kfind. The consistent one is Dolphin, and I like that. Thanks.
The implementations are app-specific; you'll need to open one bug report for this feature request in each app you'd like to see it implemented in. When you do so, please be specific about which actions you're talking about, in which part of the UI. Thanks!