As I took this I was thinking about the difference between and effect and an observation.
It seems to me that there are many photos which rely on an interesting effect – a colour or a style of presentation which makes the overall mood look appealing. Then there are others which are less about the processing and more about what's in front of the camera – an action, reaction, relationship or detail – which is noticed by the photographer and may have otherwise been missed.
In this particular photo I might say the appeal is in the effect, but I could also say that it observes the movement of the light source – an action which would not have otherwise been noticed.
Perhaps the test of a good photo which features a special effect is whether the effect or processing is done in order to reveal something in the scene which would otherwise be missed. A bad use of processing would be if it bore no relation to the real content of the image or didn't enhance it in any way.