My Plasma II has first flown in 2005, in what was a strictly VFR ship. The install follows Klaus directives and has been working without any problem.
Note, a new wording has been used here, Alternate Ignition
Yes, it requires human interaction in case the main battery circuit, for whatever reason, is or has to be set offline.
Yes, it works on IGN system #1, which means a remote possibility exists in having a failure on system #1 whilst having to switch the Main bus to OFF.
Yes, it is being checked before every flight, during the run-up procedures: At given RPM IGN 1 and 2 are sequentially switched OFF/ON, then the IGN ALT ON, and both IGN 1/2 OFF, this way the separate circuit of the Alternate Ignition is being checked under load.
The alternate ignition battery gets replaced every 2nd year as a part of the maintenance schedule.
Of course, as suggested by DanH, with today's increased reliance on electronic instrumentation, and electrical accessories, a 2 batteries elec configuration makes more sense and gives redundancy for the aircraft as a whole.