The guidance is vague for a reason - so that they can narrow it down on a later date, but more importantly, on their terms.
The way it usually works is there is a general clause that covers all the bases, and then exceptions to the general clause are defined for interpretation by your lawyer.
Of interest might be this part:
A user who obtains convertible virtual currency and uses it to purchase real or virtual goods or services is not an MSB under FinCEN's regulations
and
FinCEN's regulations provide that whether a person is a money transmitter is a matter of facts and circumstances. The regulations identify six circumstances under which a person is not a money transmitter, despite accepting and transmitting currency, funds, or value that substitutes for currency
and under
De-centralized currencyIn addition, a person is an exchanger and a money transmitter if the person accepts such de-centralized convertible virtual currency from one person and transmits it to another person as part of the acceptance and transfer of currency, funds, or other value that substitutes for currency.
My take on this is that it seems that it depends on what you plan to do with the obtained Bitcoins, not the fact that you obtained or bought them in the first place which would determine your status as a money transmitter or not.
I'm not a lawyer.
