the scripting layer has very little concern in the traditional web model, there are clear advantages to having that work done in the browser, hence the popularity of things like ajax and jquery.
why is creating any trivial website backed by a cms that isnt cuttie cooker blogger template still the domain of the ruby / phpist, we have had plenty of time to solve these problems with the traditional browser > php/ruby > mysql model, time for someone to come along with something new.
Yes, it is good thing. But will that method perfect for every use case.
Think about maintaining DB(Mysql, Sql language), Web server(Crazy config files), application server (Ruby or PHP), Client side(Javascript) just for personal blog/site.
Here layers are less and Languages(only one) and config files are less.
EDIT: "And less is good" , Arguments are endless unless you are talking about specific use case.
