There seems to be an incoming flight pattern in front of the hive, with arriving bees negotiating for an incoming landing. Individual beez fly a descending Z pattern, with other bees doing similar ahead and behind. They appear focused on the entrance, not the porch or the sloped landing board.
At times I see bees coming in very heavy, going for the crash landing on the porch, then quickly crawling in side. I don't think I have ever seen a returning gathering bee land on the sloped landing boards that came with my first "store bought" hives.
I don't see a need for the sloped landing board . I do like a 1-2" porch in front of the hive.
Some hives have both top and bottom entrances. Recently I was observing trying to figure out how the top entrances were being used. I counted many bees departing by the top entrance, but many fewer returning that way (no landing board at the top entrance). The bottom entrance had heavy traffic, both outgoing and incoming, but it seemed incoming was higher than outgoing. The suggestion from this quick observation is that the bees prefer to return via the bottom entrance, which has a 1-2" porch. Just an observation at this point, I will need to continue to observe to draw a conclusion from this behavior, and if there is a preference for returning via the bottom entrance I don't know that the landing porch is the reason.