But they're also the most addictive substances we've got. After a week or so, you now have an addiction that needs tapering to not be dangerous. If you lose access to the drugs, you might die from withdrawal.
The withdrawal can make you feel literally insane. I don't know how to explain it other than it's extremely unpleasant and everything feels moody and irrational, and sometimes you don't even realize the extent to which you're being irrational until you take more drugs and feel "normal" again.
The potential for addiction is also high because these drugs feel the best out of all drugs. You're going to want to use it again. Imagine if alcohol never made you sick or dizzy, and you could have as much of it as you wanted, and you'd just keep feeling more relaxed until you pass out. Then you wake up feeling relaxed and don't have a hangover. That's what benzos feel like.
Also many doctors don't realize just how possible it is to have a seizure during withdrawal, and some doctors will refuse patients asking for benzos because they see them as drug-seekers.
Any time I see one of these threads about benzos, I try to share my experience, because they're just so misunderstood by the general public. And it's probably not great that there's so much talk about xanax in hiphop right now.