Ummm, no. A floor jack works on the same way a forklift forks do, on hydraulics. For the same reason you use jack stands for the appropriate weight of vehicle you’re working on, you’d use them on a an irreg cart for example, the same. If the hydraulics give way or a slow leak you don’t know about, it’s usually game over for whoever is under whatever they are working on. It’s easy to not see a very slow decline on a floor jack’s hydraulic when you’re working under a vehicle.
When I’m working on a vehicle I use the floor jack as a safety, not holding the weight of the vehicle, just touching the jack spot, jack stands, and a wheel under the car for a third level of safety.