Facebook’s cautious approach is warranted, said Brian Blau, an analyst with the technology advisory firm Gartner. The Swiss Army knife model popular in Asia helps an app get big fast, he said, but the risk is that it gets bloated.

“People want ease of use,” Mr. Blau said. Silicon Valley has “moved away from feature-heavy apps.”

Uber’s integration with Facebook is fairly straightforward. Over the next few days, Facebook will be updating its app so that existing Uber users can connect their accounts to Messenger and request rides from inside conversations in the app. New users can sign up for Uber from within Messenger, a potential boon to Uber’s growth prospects. (As an incentive to try ordering an Uber car through Messenger, the first ride up to $20 will be free for each customer.)

Uber executives say the Messenger experience will be far beyond what is available in today’s Asian messaging apps.

“It’s first inning, as far as how much these apps are capable of doing,” said Emil Michael, senior vice president for business at Uber.

Facebook is banned in China, but it has closely studied Asian chat apps like WeChat, Line and KakaoTalk, which play a far more prominent role on mobile phones overseas than messaging apps do in the United States and Europe.

“What is common is this notion that messaging apps can be the place for everything that is happening in your life,” Mr. Marcus said. “The way we are going about it is different.”

Facebook, he said, wants to provide its additional services within the thread of a conversation.

“For us, it’s all about context,” Mr. Marcus said. “The way we look at whether an experience makes sense inside of Messenger is if it makes sense within the confines of a conversation.”