Mi smart bulb / yeelight

Hi.

I don’t understand. Is yeelight a xiaomi bulb ? Is yeelight works with mi home app ?

Which is better between yeelight and mi smart bulb ?

Can someone explain me all the type of smart lights related to xiaomi ? (Mi LED smart bulb, Mi smart LED bulb essential, Mi smart LED bulb... and then Yeelight...) ?

Lot of questions I know. Thank you !