Off-camera briefings “are not a substitute for the open back-and-forth between reporters and administration officials that regular televised briefings allow,” Mr. Mason wrote in his memo on Friday, noting “the need for transparency at the highest levels of government.” White House correspondents acknowledge that the briefings can sometimes have limited value as a reporting tool. But they say it remains important for an administration to discuss its actions and its policy in a public forum — even if the ritual has long been an opportunity for aides to spin and obfuscate on behalf of their presidents. The notion of reducing television coverage of the briefings is not unique to the current administration. Michael D. McCurry, who was the press secretary during the Clinton administration, has said he regretted allowing cameras into the briefings, saying the temptation for reporters to grandstand has eroded the quality of the sessions.