teams used to do alot of tricks with floors to achieve ground effect.
However, ground effect is dangerous aswell. in the 70’s to 90’s it was pretty much the biggest performance differentiator, but also a huge risk. ground effect gives huge downforce, but when you bottom out or you go over a kerb to aggresively the invisible seal of air/low pressure under the car breaks.
THen you basically go from 100% downforce to less then half that within milliseconds. This causes cars to crash violently, since you effectively went from a F1 car taking that corner at 250 to a bmw m3 that has to do it at 150 tops.
So ever since the 90’s they basically closed this avenue of development. They made everyone have a standard floor. A woodenplank in the middle of the car.
TO make sure people didn’t run it too low they were only allowed to lose a certain number of MM of this plank per race, or be disqualified.
They changed the parts where the woodenplank makes contact to the ground when it bottoms out with titanium skid plates. Which instantly scrubs off a bit and gets superheated and turn into these sparks.
AFAIK, the only reason was that we’d get nice sparks, the wooden planks were doing their function just fine.
the wooden plank still exists if you look at that picture, just small parts of it are titanium to make sparky sparks