Unfortunately, there is a contract that once you buy this motherboard, you must install the WiFi card!
No, seriously, if you don't want to use it, don't install it. It will not negatively affect the board's operation.
However, I would consider that you can always install the WiFi card/antenna and simply disable the M.2 Socket 1/Key-E (unless you need that slot for something else). If for some reason you ever need to use WiFi, it will already be there and it would only require a quick trip into the BIOS to switch it on. It might save you a little hassle down the road.