It is indeed functional now, except for a couple HTML bugs (Button not working and link appearing white against light grey background) that will be fixed a bit later tonight as another task that required attention came up.
But yes you can follow the instructions now and begin collecting.
Begin collecting officially? Or simbolically, or testnet?
I think you shouldnt tell anyone to start collecting without doing it in an official way. This gives a very unprofessional perception, as no one knows when people can start doing it, until when, how Jinn donators can recollect, should anyone really send real btc even if its a small amount for a testnet?, web with bugs still, etc.. There is nowhere to find all the conditions and instructions on collection.
Marketing-wise this gives a very bad image, of doing things as they come without planning.