Access points and range extenders are both used to increase Wi-Fi coverage, but they are not positioned the same way, nor do they provide the same performance and support the same number of users.
Access points are all around better than extenders since they can provide much higher performance and support more than 200 users/devices each. Range extenders are typically used in homes and provide a boost in signal, but sacrifices overall Wi-Fi performance and supports no more than 10-15 users/devices.
Note: Access points should be wired to a switch or router for best performance. You can use meshing on access points, but it doesn't work near as well as hard wiring.
Access points allow you to scale your business up or down at any time. Newer access points can also be powered through an Ethernet connection making a separate power outlet unnecessary.