What exacly Lemfo Lem X do ?

Hi there all, 
I wonder if there is something that I don’t understand. 

For example if the Lem X have no a SIM card, and if I connect the Lem X to my mobile phone via BT 
it let me know when I receive the calls ? 
Can I answer at calls via BT from the Lem X ? 

Can I receive notification of WhatsUp, SMS, Facebook etc… messages on Lem X ? … also can I read them ? 
When I receive notification, it’s only vibrate or I can hear the sound notifications ? 

Lastone… little OT… is there another watch with big display like Lem X and maybe more powerfool ? 

Thanks all Denis