That it can be purchased with fiat. By accepting dollars for Bitcoin those who control dollars by extension control Bitcoin. At least to some extent; thankfully the system has inherit structures to mitigate monopolization.

Over a long enough period though it is hard to turn a blind-eye to the recipients of infinite fiat money and what they are/might/can do to consolidate/control all aspects of the ecosystem (or to literally torch the world around the ecosystem rendering it a moot point when all is said and done).