Lightify need it's own hub or ok now direct to ST?

I have a few GU10 Lightify directly connected to ST (don’t own the Lightify gateway). I do notice sometimes that the lamps are on and can’t see why.

I know the Lightify gateway is for firmware updates but is it for anything else?

If I bought a gateway can this be used with ST for better control? Or is it just to update the firmware and then direct back to ST?

Does ST update Lightify lamps now without the gateway? Read earlier it was planned? If so how do I enable this or look for firmware updates and what is the latest please.

If not is it worth me getting a gateway (can get one for around £15), just to get the lamps on latest firmware and then disconnect the gateway and use with ST direct