PHP miniframeworks: do we really need them?

PHP microframework are the buzz word of the moment. I saw the trend grow in the Ruby and Python world with projects such as Sinatra or web.py (the latest being a lightweight framework to be precise). Honestly I still don’t understand all this interest. I reckon they might be interesting as toys suitable for playing around and testing little features. They are perfectly cool for little gems such as Sismo But I don’t see them fit any serious project in web agency teams. The main reason I have against these frameworks is the lack of a convention which is usually enforced by larger projects. We will see if there is going to be a wild interest for such pieces of code and if they will see a broader adoption. What do you think? I’ll keep on investing my time on Symfony2 in the mean time.