It works fine and is even supported in the official BitTorrent clients nowadays but it's correct that BitTorrent wasn't designed to stream and streaming was con

It works fine and is even supported in the official BitTorrent clients nowadays but it's correct that BitTorrent wasn't designed to stream and streaming was controversial in early BitTorrent. Clients are meant to prioritize the rarest pieces in the swarm first with some randomization thrown in. Downloading sequentially is bad for the swarms health but as it turns out doesn't seem to be bad enough that the protocol can't handle it, at least as long as there's a mix of streaming and classic clients or streaming clients use a combination of classic and streaming behavior.