2 of the light bulbs died quickly and their app is terrible subscription bloatware.
At first I plugged 4 light bulbs, I managed to connect to them via bluetooth, but it is highly limited. You can only control lights 1 by 1. If you want to group them you need an account and access to the wifi. Since I don't want them on my wifi I accepted the fact that I would control them 1 by 1. And now the app keeps asking me to enable notifications, why would my lights need to send me notifications?
BUT, now you NEED an account to add more lights. So I can only control 2 of them with the app and the other 2 needs to be turned on manually without any control on the intensity or colour.