Linoleum works, too. I will probably still cover the wood shelf with something that is easy to clean off like linoleum, but I wanted the trays on top because they are super light and can be removed easily and hosed off outside. The shelf is a lot heavier and cumbersome.
There are two basic schools of thought in the poop collecting field (heh). One approach uses a fixed board. Poo is scraped off with some kind of putty knife or trowel into a bucket or some container periodically and removed from the coop that way. The other approach uses a moveable tray or board of some kind. With this approach, the whole tray or board is taken out of the coop with the droppings on it, taken somewhere else (in my case, over to my composter) and cleaned off. Removeable poop trays/boards are best when they're light and easy to move.
Either way works, it just depends on your preference. Personally, I think it's easier to get a removeable poop tray cleaner. When you scrape poo off something, there's always some left behind. With my boot trays, I simply hose them off outside before replacing in the coop, spic and span. I couldn't do that with a fixed poop board without getting the inside of my coop wet, something I don't want to do.