That sounds like a good way to go about it. With the way home assistant store data it does not even make sense to store all sensor data, so polling at n interval will be preferred in most cases anyway.
I agree that for real time data MQTT is probably the best way to go. That would not even need any special ruuvi integration or setup (at least not if the gateway supports mqtt auto discovery). If we where to push data via HA’s rest or websocket api there would have to be extra setup so might as well spin up a mqtt broker at that point.