Would you consider adding this?
E.g. "Show|Hide" if "Device" is "Desktop|Mobile|Tablet" by adding CSS3 classes:
.visible-phone
.visible-tablet
.visible-desktop
.hidden-phone
.hidden-tablet
.hidden-desktop
Don't know how to code, so I can't do more than suggest ;)
http://wordpress.org/plugins/widget-visibility-without-jetpack/