Is Kodi hooky?
The as it comes Firestick and other similar devices are not, but you can sideload things onto them that have naughty uses, such as streaming and downloading copyright films. Kodi is one of the better known bits of software, which has legitimate uses, but you can add things for downloading and streaming via Kodi. You can also add things which work without Kodi.
Downing loading involve peer to peer, which ISP's tend to jump on. Streaming serves it up for instant watching from one server, whish ISP's tend to ignore, but streaming is much less reliable and less reliable continuity, than downloading.