If you have a trailer that rides low to the ground and you only need 1 or 2 steps, it's a valid point.
With a lot of the modern trailers where you need at least 3 and often 4 steps, the leverage results in a diving board effect, particularly on the bottom step. On a prior unit, we took to putting a jack stand under the last step to minimize the issue. With the current trailer we have the new style that folds up into the door and they are so much more stable...
From the manufacturers point of view, it makes floorplan layouts easier as the underhung steps need appropriate frame attachment points. The fold into the door steps can go just about anywhere.
PS: Queue the claims that you just need to buy the good version that defies the laws of physics....