Valid points and yes, picture quality is the most important thingI can see the value of a siren and flashing lights such as on Dahua active defence cameras. However, I equally see these as a niche rather than a mainstream product. The flashing coloured led degrades the picture and ruins recognition. Clear led's better in this regard but not sure how much they really add to the overall picture vs quality. I see this feature as more something like you'd see on a Ring ie best activated by it sending a notification to your phone and you manually viewing the video and then trigering the light / siren or alternatively activated after a longer period of activity when you've already got the money shots. Having it activate on detection or 5 sec thereafter is detrimental to the picture and whilst it might stop an attack dead, it can also ruin the evidence.
My personal use for one of these cameras would be as a rear yard defence tool as then any activation means you've probably a) already got them on other cameras and b) you actively want to scare them out of there, or as a backup camera to another camera where the delay is such that the other camera gets the money shot and this one scares them off, or as suggested manually activated.
I certainly wouldn't want even a clear led on all night. I'm trying to cut my electricity bill not increase it and as mentioned the downside is you're potentially considerably shortening the life of the camera runnign leds for long periods becasue eventually they will fail like any light source.