Are smoke detectors a waste of time?

I am very keen on safety (having been an engineer in the construction industry), however, I must confess to disabling or removing all the smoke detectors we have ever had in caravans.  I know that one or two people have had electrical problems in their van in the middle of the night causing smoke and the detector has alerted them BUT, who in their right mind would fit a smoke detector in a confined space right opposite the cooker?  OK in a house where you are sleeping upstairs and there could be a fire downstairs and you get trapped but in a caravan surrounded by windows and (in our case) a great big open skylight above us?  Maybe a CO2 detector might be of more use judging by today's tragic camping accident (although that was in a tent)