As for the debate . . . I think we should review C-Dan's post because he makes some good points (pun intended) . . .
First, a thyristor based ignition goes beyond replacement of the breaker points with a solid state electronic trigger. These units use the stock breaker points as the trigger to a capacitor that runs on as little as a few volts input. This capacitor can provide 30x the voltage of the battery to the primary winding in a stock coil - which means that the secondary coil winding firing the the spark plugs puts out a considerably hotter spark - and the setup doesn't degrade at all over the rated RPM range.
As for the emergency repairs debate - look at the circuit. The gizmo is installed in series on both sides of the coil. If it fails one can re-wire the gizmo out of the circuit and drive away on a stock points ignition - with no visit to a parts store.
Not my cup of tea - but I understand why some would choose the setup . . .
regards,
stock49