Everything has upsides and downsides, right?.
A EFT target as well as a FT target can malfunction in a number of ways. Those of us shooting in these comps have seen most of them.
Not in order of prominence.
Screws or bolts coming loose.
Screws slightly tight or mechanisms rusty causing binding so the target fails to fall all the way.
Strings or clips popping off so target can't be reset.
Target is loose meaning not attached to the ground or whatever else it's fastened too. Might or might not fall.
Very slight splits on face can allow a target to fall anyway. I've watched this more than once because I saw the paint come off on edge of the faceplate where I hit.
One time there was a hole in the paddle that I didn't see and I shot through it both shots. That was a real head scratcher until someone else noticed the hole and alerted a RO.
There's more I'm sure.....
A spinner.
With a spinner the outside of the pellet, if barely contacting it, will move the spinner a tiny bit. This may or may not be noticed by a person spotting. I've been bit by this a few times where points were lost or in a speed event the wiggle of a hit was not acknowledged.
Or I hit the stem holding the spinner which shouldn't be called a hit.
But no strings needed which saves time and effort in a number of ways.
No question a well made spinner is more reliable than a more complicated mechanism.
Often it's easier to see where one misses in the dirt behind the spinner vs not seeing where one missed on a shot up FT target so a sighting correction can be made.
A larger caliber will be at a slight disadvantage on a faceplate which is the same size as a spinner. A smaller caliber will have a slight disadvantage on a spinner target. A spinner can be sized smaller to approximate the same difficulty as a faceplate hole.
However if everybody were all shooting the same course what difference does it make what we are all shooting at, KZ's or Spinners. Someone is going to win regardless.
As much as I like EFT and FT targets, I like spinners more. I also like bell targets more than EFT and FT targets. I love the ding and the spin and no strings or ropes to deal with.
A light indicator is a interesting way to go about recognizing hits. I'm not sure a light going off when there's a hit matches the excitement of hitting a spinner or knocking down a EFT target though.
Plus batteries need to be replaced and at some point the flashers will start malfunctioning or break as well as other potential problems that have been mentioned.
Kinda feel flashers are better for ELR than inside 100Y.
Hey combine them all and it'd be like a EFT arcade.