I have a deck of Ulu Watu clan and their bonus is +2 power... Is it effective/ working???

Yes
Maybe you got randomized thats why your loosing....anyway if you like to win without random...there a room called danger zone

After all I have seen: yes, unless it is cancelled.

Yup it works Gg

Yeah, it really does. Though in my opinion, it seems to be bad luck in rooms where the randomizer is on...

You should try in in the danger zone, though.

Ahh ok... What happen if the room is not randomize???

You'll kick some serious butt because you'll be able to use cards with up to 10 power.

Then the room is not randomised and the higher power card wins. (I wonder how this could be read differently, care to explain?)
The only room where this is the case is the Danger Zone. At least right now.