You're absolutely right, I spent most of the past three years writing Java, C++, C, and C# and they all use semicolons and I certainly forgot about them whilst coding in those langs. But the penalty is in transitioning between languages that use or don't use those features. When I'm writing in C and the like, I tend to stick within that language. But with JavaScript and Ruby, I do a lot more context switching back and forth. Anything I can do to reduce the penalty of moving between one and the other is worth doing in my opinion. Especially when it doesn't affect the final result.