It perfectly shows that this is nothing more than an attempt to buy time before they eventually pull off another 'hack' hoax. For years Bitfinex has been unwilling to license itself properly, and in order to lower their overall governmental risk exposure, excluding US customers is a necessary step that has to be taken. I however don't believe that this will help to shake off the US authorities. Bitfinex has been offering its services to US customers for years, and that alone is reason enough for the authorities to look into their 'administration'.
I think this is pure conjecture. Most people involved in Bitfinex are known (e.g. Potter, Hoegner) and would have to look
over their shoulder for the rest of their lifes if they would actually pull off a "hack hoax".
They have one of the best trading platforms and are making a killing in trading fees. Additionally, I suspect
they trade on their own exchange as well and quite possibly profit from buying up sketchy altcoins
before listing them for trading. Just take a look at some of the recently added trading pairs and you will
see that they started listing some obscure shitcoins.