The reason we use such tactics is to increasing barrier of reverse engineering because our teams value their work. Some people claim that security through obscurity is bad. I challenge this view. I claim that every security defense such as RSA is a obscurity.
It's a matter of time until RSA breaks in the same way as Obfuscation does.
Gmail is not your let's make it weekend kind of app. It's highly sophisticated and deliver huge value.
There are lot of people who hate Obfuscation. Some are communists and others are attackers.
My wife (she works in the fraud detection department) found an interesting attacker who masqueraded as a security researcher and student of X University, but in fact he was a a criminal scum. He has reverse engineered anti-fraud scripts of many websites and published them on Github for everyone to see. His main goal was to attract malicious buyers and sell them scripts that bypass this protection. It was one of the heck of marketing.
Brian Krebs also had similar story on his blog.