The reason not to use VLAN 1 is that there’s a concept of a native VLAN and VLAN 1 is normally the default native VLAN as well as the default VLAN for any unconfigured port. It’s easier to just not use it. The OP has used it for their existing VLAN. The biggest problem with that is that the management VLAN for the AP would be the same as the tagged VLAN for the wireless clients potentially allowing a WiFi client access to the management port of the AP.
The reason not to use VLAN 1 is that there’s a concept of a native VLAN and VLAN 1 is normally the default native VLAN as well as the default VLAN for any unconfigured port. It’s easier to just not use it. The OP has used it for their existing VLAN. The biggest problem with that is that the management VLAN for the AP would be the same as the tagged VLAN for the wireless clients potentially allowing a WiFi client access to the management port of the AP.