The Z2M team complied with a design decision made (some time ago) by the HA team regarding how a physical remote-control device should be modeled in Home Assistant.
The use of a sensor entity, to report the remote-control’s button events, was deprecated in favor of two alternatives.
The preference is to model it as a device so button events can be detected by MQTT Device Trigger (and the button events are self-documented). The other way is to model the button events using an event entity.
As you have already discovered, making the switch from sensor to event is fairly straightforward.