It is absolutely possible to use FreeNAS without RAID by configuring each disk as its own volume. We don't tend to encourage that configuration, though. We assume the reason you're using a ZFS-based NAS OS, with the admittedly-high hardware requirements that entails, is because you care about your data and want to protect it.
There are a few counterpoints to consider: (1) disk space is cheap. Yes, you sacrifice some (usually on the order of 1/4 to 1/2) for redundancy, to protect your data, but in the grand scheme of things, that doesn't cost very much. (2) disks are big now--6 TB disks are quite affordable (on a $/TB basis, not significantly more expensive than 3-4 TB disks), and even 8-10 TB disks are available. (3) unless you're looking at many tens of terabytes of media storage, you can probably meet your needs with 4-6 suitably-sized disks, which really don't take much physical space at all.
One point I'll correct you on--a striped pool (which you call RAID0) won't result in any given disk failing any faster than it otherwise would, but it will shorten your average time to data loss. The reason for that is that when any single disk in the pool fails, your entire pool will fail.