Well, yes, their fees are much less eye-watering than say, the College of Arms.

It is generally conceded that to have any sort of standing, arms need to be granted, confirmed, or recorded, by some sort of government authority. Assumed arms, or those devised by private bodies such as the American College of Heraldry, have no substantive basis in law and are therefore "not recognized" by the heraldic officers in the various offices of arms.

Something that I have always found amusing is the snobbery associated with "who granted your arms". No one office of arms has a monopoly on the nobility associated with a grant of arms. All granted arms are equal, and granted arms have always been the threshold of nobility, one that any virtuous and well deserving person may cross with comparative ease.