@hjalfnar_hgv Well, it has not helped me once, and in my opinion, its functions are rather unclear. To me it looks bugged, because I a) don't see useful effect b) there are no visible indicators to inform the player that the ability took effect.
Additionally, you said it jammed their sensors only for a few seconds. What kind of useless ability is that? In my opinion, in order to be useful, jamming should last 20-40 seconds.
"A few second" is like that time, 40-60 seconds i think, it's pretty useful especially early game in the campaign for Space Marines before you get the ability to run silent with Strike Cruisers. Just activate it before getting into view range and you are able to close to boarding range before the enemy is able to identify you. It's also great if you have to run after boarding, trigger it and the enemy fleet won't be able to fire at you while you make a run for it.
Also there is a visual effect on the enemy ships, little sparks.
the enemy has sparkles around their ships when it worked
its very situational but it can be usefull
if your running a stealth fleet you can trigger it just before you go in and would otherwise reveal yourself to kill a ship off safely
i have used it effectively once
its not great, and i wouldnt advise it, but it has a niche