My take is that no & yes. It is not a requirement unless there is a need for fast roaming to accommodate seamless transfers of connections as one moves about (think streaming such as with voice or other real-time applications). Otherwise, it will be a nomadic roam where a new AP will need to be found and a re-authentication process started to connect to to same. How long that may take is determined to some degree by the authentication type required. Additionally, there is then the question of when does the actual need to shift to a different AP occur? As you get further away from the AP that is currently in use, the signal level will drop, but the devices will likely try and maintain the connection by dropping the speed of the connection in the meantime. The decision to shift may be a setting within the client WiFi connection for roaming aggressiveness or similar. Also keep in mind that not all devices may be 5ghz capable.
So, from a practical standpoint of wanting to have the best overall setup from where you have the control to tailor the network to have the best coverage for you area, obstacles and other factors with the best throughput and least interference with virtually seamless roaming for those devices that support the fast roaming standards, then yes, it is needed.
If you do not have the above need, and have the device whose client WiFi cards allow roaming, then no. However, why would you not want to use the tools provided anyway?