Taking from my experience, the default action of widgets triggering code execution upon value change poses risks that outweigh the convenience in certain scenarios.
While this feature may seem advantageous in some cases, it can lead to unintended consequences and a less controlled development environment. Having a widget's value change automatically trigger code execution during the midst of development or maintenance can have significant ramifications if the code is not adequately structured or tested. Moreover, it becomes even more problematic if the inattentive user fails to perceive that an execution has occurred.
Given these considerations, I believe the default behavior for widget value change should be to do nothing, or at least make it so that the user can customize this setting in their preferences. Additionally, implementing a visual cue in the IDE to indicate that widget changes will trigger code execution would provide developers with a clearer understanding of the potential impacts of their actions.