TdF Stage 11: Lakes and Jet Skis

I am getting a bit muddled with the stages. But we are now up to stage 11. A beautiful ride through the Jura mountains. Past magnificent lakes. You might have noticed the pleasure boats and jet skiers on some of them as the peleton whizzed by.

At the risk of alienating some of my Blipmates out there in Blipland- jet skis: why ? I don't get the attraction.