Sprinklers are not technically fire fighting equipment though. It is suppression, or simply a means of controlling a fire to a specific size. It MAY extinguish the fire, but there is no assumption made that it will. This does have the effect of protecting relevant persons, especially neighboring premises etc as the fire should not grow beyond it's set size. This mean you have got measures to mitigate the effects of fire.
Sprinklers do not replace the need for FFE, but the 'naughty boys' reason for having less in your example is a valid one. (Legislation-wise IMO you are successfully hitting the requirement of "take measures for fire-fighting in the premises, adapted to the nature of the activities carried on there" Even without sprinklers I would consider this reduction. Look at the average pub, do we have FFE at the exits for people to pinch/activate/use as weapons? Nope, we tend to stick them behind the bar out of reach. if they are stuck behind the bar then what is the point of having 1 per 200m2 of floorspace, considering that we advise people that if 1 hasn't put the fire out then it is time to leave.