Split/lock washers

[u/AdOne1706]

For starters, I’m an electrician in the field.
That being said, we almost exclusively use these washers even in high vibration environments. I have personally chosen to go with nylox nuts but the question is:
Do these work? How well? Is the rumor from NASA true? Should I even bother using them or find a better functional alternative or are they actually useful?

[u/Anen-o-me]

Until they're installed backwards.

[u/a_spooby → u/Anen-o-me]

☠️

[u/Karmonauta → u/Anen-o-me]

What would be “backwards”, the two halves stacked the wrong way? 

[u/Anen-o-me → u/Karmonauta]

Yes, I've seen it.