Inspired by @tompoland results I thought I would give this a try for myself. I purchased 2 Ionisers. The one on the left has the Ionising fibres poking straight out the end, the one on the right has 2 power settings and seems more expensive, but has the fibres Horizontally in the little circular area at the top.
Now it might be simply that the left one works and the right one just lights up an LED, however the left one definitely produces results. The right hand one, not so much.
Grinding into the portafilter, no Ioniser
Grinding into the portafilter, left hand Ioniser with fibres pointing down and towards the exiting coffee grounds
Grinder used Niche Duo, coffee was a Brazilian Daterra. Grind medium to fine. I think the results are pretty conclusive.