i think Norwich or perhaps it was Exeter has something similar. Jokes aside I believe it’s so they don’t need to purchase an ambulift as it’s actually just a ramp so wheelchairs can come on and off. The ones I saw had stairs on the side for time pressed crew/staff to take a shortcut
The one in the photo also has stairs on the side for the reasons you have mentioned.
Southampton Airport also have similar ramps to the one in the photo. As ridiculous as they look, surely they are more practical than regular stairs. Especially for the elderly and for those hauling a bag or even wheelchair bound.