Is UNA a replacement for version control systems?
No. Although UNA enables developers to edit the same document at the same time, UNA is not a replacement for version control systems. UNA is designed to function in combination with a version control system. A version control system is necessary to isolate development code from production code, to provide powerful reversion features, to enable developers to put feature development on hold while they fix critical defects in the software, and to enable large-scale (but non-real-time) collaboration.