daily everything (programming, gaming, whatever else flies my way)
good, wouldn't recommend this in particular to new people unless they aren't afraid of a steep learning curve
privacy, more control over my system, and my computer finally does what I tell it to. (Even if sometimes it probably shouldn't, but then that's on me). Oh also: it makes programming so much more enjoyable. Need a dependency pacman -Syu whatever-i-need, done.
Probably the installation of the distro itself, since it doesn't have a graphical interface that most computer savvy people are used to. I've heard that nvidia driver installation used to be complicated, and it's usually necessary to employ command line for that. And even after you install Gnome or KDE, you'd still probably have to use bash for many, many things that you want to adjust or install. Oh, and since it's a rolling distro, it can easily stop working after you update it.
That's what I know, I've never used Arch myself, been sticking to Debian-based distros for now.
Re: rolling updates breaking stuff. Doesn't really happen. If there's an issue updating there's usually already an announcement explaining why and what to do. Also, Archwikiist just great.