If not necessary, it should in doubt not be destructive. As Kazakore pointed out, you still CAN edit the original and thus also the slices, and once you “render” slices down to real samples, you can’t edit anything fluently anymore.
But hey, if that’s such a big issue for many people, making the whole feature “totally unusable”, then we should try address this and allow rendering slices without tools. I doubt that alone is the problem though, because you can workaround this. Maybe you simply have no need for the feature in general in your workflow?
Another related feature, that was asked for many times (and which also got realized as a tool) is the ability to write down the sliced instrument into the pattern as a starting point for slicing up beats in the pattern.
As useful this is, the main reason we did not added this, was that it’s hard to integrate into the instrument or pattern workflow. Where would you look for such a feature? In the pattern editor’s context menus, somewhere hidden in a sub menu? In the sample editor? You don’t see the pattern, don’t know where it gets added in the pattern when invoking it from the sample editor.
If anyone has an idea how to properly integrate this and how to “name” it to make clear what it is, then I’m all for this as well…