All MSBs have to register and are then subject to expensive fees and regulatory practices by their states.
This part ("are then") is not quite correct.
The state and federal laws are disconnected, even if they are intentionally similar in many cases. Becoming an MSB or MT at the federal level does not immediately trigger a state requirement. A state requirement to -- for example -- undergo a background check or provide a surety bond is not triggered by becoming an MSB. The state requirement is triggered by... your transmitting money in a regulated fashion.
A couple US states do not require money transmitter/MSB-like licenses, leaving only the federal requirements to handle.
For those curious, this is the actual federal form.