If you test your software built on Zig close to 100% then you can be pretty confident you didn't run into any of the Zig compiler bugs. Bun has certainly run into them but they can almost always be worked around... if you work around all problems and manage to catch everything then yeah, you can have an application that's production worthy while being built on a compiler that's not quite there yet.
The problem is, of course, you almost certainly didn't test anything near 100% and probably not even everything users may do with your software, so it's a risky bet.