Hello,
I'll soon go to the USA with my mavic, and I was wondering if I still have to register my drone at the faa. I've seen news about a cancel after a law case, but on their website we still can register. So should I do it ?

Don't have to b/c of the recent court ruling but that this point, it's an option.

Registration and putting your reg number on the AC provides for a possible path of return for the drone if you lose it, but that's about all it's worth these days. Not required, and those that already registered may request their fee back and their record expunged from the database.