(Art and Yeti)
I have never had to use carbide and getting the carbide itself is a problem.
The way the water drip to generate the gas was regulated seemed a little fiddley to me too, but that is the nature of the lamp.

Yet consider that something which lasted so long as the standard hatlamp for underground miners obviously has some good points.
Especially since it was only replaced when light weight rechargeable 12 volt battery packs able to last 12 hours became available.

I expect the 12 volt lamps used underground by miners now will all be replaced by led versions soon too.

Chemical light sticks would never stand up well enough in a mine to be useful. They would all be broken and glowing less than 100 feet inside the portal.
If it wasn't for the fragility of them I could see them being used by miners as backup lights instead of Zippo lighters.

I can also see Art's uses for them in sport caving as trail and hazard markers very well.
I suppose if you wanted to light a sump or check it for how strong of a current it had they would be nice there too.

People tend to choose their opinions based on their experiences and I certainly would't reject either of these opinions without at least giving them some consideration.

I said earlier, all of the really good uses I had seen for chemlights were people lighting themselves up so they would be seen.
Then
Desperado told us about using them for lighting a helicopter landing zone, and after I thought about it I realized we do that in the northern mines with permanent tritium powered lights.

Art told us about using them as hazard markers underground.
Other people added other uses too.

I have learned a bit on this thread, and as Yeti says, it is nice to see the discussion coming from different viewpoints on it.