They say brass can sanitize, but assuming it’s not that…

Its easier to clean and will prevent wear on the door itself.

Smooth surfaces such as polished metal have fewer areas to harbor bacteria compared to the fibers of a wooden door, for instance. In addition, a flat surface is easier to clean than a round knob.

Another benefit is that some metals have a natural antibacterial property toward bacteria organisms on their surfaces.

Doors that push open are a lot more amenable to panickong people who need to get out in an emergency. You may notice that a lot of these non-latching or push-mechanism doors also swing out towards the exit.