hollywood writers can't understand simple engineering and physical problems like "energy density." so, no, until they solve the battery problem, these are toys. possible best use is as automated sentriess. which no one sane will use after the first few friendly fire incidents.
so what you're going to want to study is "security fog." there are variants that scatter IR light. or "uv lasers" which destroy the CCD chips in cameras in seconds.
finally.. one of my old school favorites.. the "magnetic mine."