yes, obviously not all devices have battery levels. for me, at least, many do and this is a field i like to keep an eye on. at least having an option to include this field in the devices display window would be useful for me and seems to fit the spirit of the current indigo design, as i understand it.
i see "Last Updated" field is supported, though for many of my devices, that doesn't have a useful value. ditto for Firmware field.