IMO there is nothing unreliable about optical triggers. They have been around for a very long time. I had a Unilite back in the 70's and worked flawlessly. We use optical triggers for a variety of far more critical things than ignition circuits with 6 nines reliability. I might also point out that optical triggers are used routinely in high noise environments (like ignition systems) to achieve such high reliability.

The Hall efect itself is not digital in nature, that comes from Analog to Digital conversion of the generated voltage signal which is typically an impulse, square wave, or sinusoidal in nature. Most all ABS and speedometers are now using such signals and they too are extremely reliable.

Embrace the technology, it works, don't be scared of it.

Kitz