From a bit of looking around, I suspect it may applicable for lifeboats used in oil/gas applications where the lifeboat could be launched into waters engulfed in flames from burning oil/gas on the surface of the water. There is a video demonstration at [1].

Even though people working in the proximity of a fire resistant lifeboat would already be comprehensively trained to operate said lifeboat, perhaps they've found that people forget and need a reminder to turn on fire suppression sprinklers in the... heat of the moment.

[1] https://www.youtube.com/watch?v=BXYL-X4SHN4

I guess it's not used to spray the boat, but the water surface. I'm no expert on this matter, but I think it breaks surface tension somewhat.

I have seen people disturb the water in a pool before a high diver jumps, so I think this applies here aswell.

From what I could find lifeboats have sprinkler system which pumps water over the outside of lifeboat for safer passage through water surface fire.

During a fire maybe?