[monopede]

Note that in many dynamic languages (and I think that includes PHP), syntax checking is done right before you try to run it, and type checking is performed at runtime. When you're programming in a Java IDE, these kinds of errors (and related ones, like typos in variable names, etc.) all get resolved while you're typing. In PHP or JavaScript you only find out once you run the program, so saving 3 seconds can be a huge win.

Of course, you can do static analysis to some degree which would cut down that time even further, but you may also get false alerts or miss some issues.