It is perfectly legitimate. It just saves an interim method call
JspWriter extends java.io.Writer. java.io.Writer provides the method "write(String s)" Most of the print* methods will just indirectly call the writer. The print method has to be used for expressions, because you don't know the type of the argument. With template text, you know the type is String, so can use the method write. Also the print(String s) method is tasked with printing out "null" if the argument is null. As you know the argument being passed is not null, you can just call write directly.
So they save an entire method call, and an if statement for every out.write() they use instead of an out.print(). Given the amount of times this happens in a JSP, it seems a worthwile optimization.