Some people like using poop boards and some people don't. You can do it either way.
For people that clean their coop regularly, instead of using the deep litter method or methods, using poop boards extends the time between clean-outs.
In a deep litter coop, using poop boards reduces how much litter you need to add to the coop or how often you need to add litter to the coop. The chickens will still be pooping as they walk around in the coop, but you will be removing the larger amount of poop under the roosts.
The down side to poop boards is that they stink if they aren't scraped frequently and daily seems to be the most common choice. If you leave that poop sitting around on a board, it will begin to stink as badly as a dirty coop that needs to be cleaned or a mismanaged deep litter coop that needs more litter added. It will stink more than the poop would if it dropped onto litter below the roosts. As long as you clean the board off frequently, no problem. If you can't or don't want to do that, I would either skip the poop boards or try using bins/trays that contain some litter under the roosts, that can go longer before being dumped. That works, too.
That's really where the choice comes in. Some people are happy to clean their boards frequently. Some people want or need to save money on litter. Some people just don't want to scrape poop into a bucket every day or couple of days. Some people would rather do their coop maintenance on the weekends or they need to, because they work long hours or have long commutes to their jobs. Others just want to toss a scoop or two of litter under the roosts, as needed.
Whatever you want to do will work great. There's nothing wrong with doing it one way and changing how you do it later, either.