These reasons, plus there is little to be gained by an adversary revealing capabilities so closely. One possibility is that this is intended to reveal to the C

These reasons, plus there is little to be gained by an adversary revealing capabilities so closely. One possibility is that this is intended to reveal to the Chinese that the US has drones capable of intercepting naval vessels, in order to dampen adventurism in the South China Sea. By doing it this way, they avoid the risk of a drone being captured and the capability being properly evaluated. This would create maximum uncertainty. It also reduces the justification for posturing and overt escalation.