You would think they would have more to do than spy on people.

I hope they don't waste time for that; many crimes are committed with only hints who they are looking for, possibly even someone who's otherwise wanted,and surveillance of an area in which a suspect is known to frequent, the places he goes, and the hours he is known to keep, could result in catching a suspect or even a cooperative witness who can point out a perpetrator.

If it works to stop crime, it’s useful.

Just recall that privacy and human rights can be sacrificed to do that -- and when a case comes to trial, even result in dismissal of charges.

Hello everyone! I find this drone thing rather dubious.

In what way?  The use of them or you don’t believe people are using them at all?