You can set up dynastic organizations which model mercenary groups and underworld organizations; those are two of the archetypes. The problem is the two scales (personal and organizational) don't map very well to each other: dynasties play out through time in 30-year increments (smaller actions tend to resolve in months and years), and their access to resources is fairly glossed over. How much money does a dynasty have access to? Um, lots? How many people can it muster? Er, again, lots?
Dynasties are useful tools for driving a character-level campaign, or playing out a campaign on their own level, but they aren't particularly useful for accomplishing specific actions on the individual level: they're just focused at too high a level to really pay close attention to the low-level stuff. Yes, a dynasty can swat an individual character; it'll probably do it by sending out a couple of operatives or offering a contract and letting the lower echelons deal with the issue.
Now, one immediate use I saw for Dynasties was resolving an age-old debate in the Traveller community: if the Imperial Navy is there, why does piracy still exist? Answer: there are criminal organizations, very powerful criminal organizations, supporting and organizing it. Organizations which can be modeled with the underworld dynasty rules... If the pirate-supporting group is on a similar power level as the Navy, or even locally more powerful, then the pirates have a fighting chance... as long as they don't step out from under that protective umbrella.
