I was told years ago that slamming the action shut in SXS or O/U would wear it out faster.
True or Not I do not know. I am sure a soft closing
would be better than slamming shut.
However I have just held the the lever right and closed action and released the lever on the closed action for the last 25 years and see no disadvantage or find it a hindrance in anyway. Occasionally a shell will be tight in chamber and require a snap shut. Also I have seen on several occasions SXS discharge on just closing the action not to heavy handed . Bad sears or whatever. So I will just continue to hold the lever.