Bit Torrent alone is not safe to use because people can easily put viruses and other unwanted programs in it. If you take the time to review each thing you download and scan it with virus protection then it becomes a lot safer to use. It still won't be 100% safe but at least you are doing what you can to make it safe.
Yes, BitTorrent is safe to use, because there are not many stories any more of people downloading bad things, or having trouble with viruses. BitTorrent is similar to streaming these days, in that most people do not have a problem with the things that they download. Streaming might be just as easy, but yes, BitTorrent is safe to use.
Almost everything is safe if you know what you are doing, and Bittorrent is the same way. Sure, there are many ways that people can get hurt or do something illegal and get caught using bittorrent (even though they shouldn't be doing those things as well), but being careful and knowing how to be safe is possible.
BitTorrent is not inherently safe to use. It is never fully safe to use sites that allow you to download illegal documents and steal other peoples work. Among the ability to get viruses and other malware type files, you can also be tracked and charged with stealing these files. So it is not safe.
BitTorrent is illegal and it should not be used. It is illegal to distribute licensed materials without paying the royalties to the original owner. Although uses of this protocol are not usually prosecuted, this might happen in the future. It is better to do things legally rather than to take risks.