imo I should be for real time observation and referencing a specific thing.
I've worked in places that had to have cameras everywhere but also had strict prohibition on viewing the archived data, because it was in a hospital setting. and people's privacy was a legal issue
i don't think it should be used to monitor people without cause basically
tape storage is for offline storage, and any data storage on it would also be redundant
writing and reading tape archives takes a lot of computing. usually you have your tape library server and a server hosting the app and then the tape sled. tape takes a lot of energy
so deleting it electronically is going to take a more energy
it's more efficient to overwrite it or use a degaussing device to wipe the tape
while it's an appliance and therefore power hungry, it's by far the most efficient at its task (heating and cooling large volume of air)