Why use output buffering in PHP?

Question

I have read quite a bit of material on Internet where different authors suggest using output buffering. The funny thing is that most authors argument for its use only becaus

Answer 1

The most obvious use cases are:

1. An output filter (eg ob_gzhandler or any number of filters you could devise on your own); I have done this with APIs that only support output (rather than return values) where I wanted to do subsequent parsing with a library like phpQuery.
2. Maintenance (rather than rewriting) of code written with all the problems you discuss; this includes things like sending headers after output began (credit Don Dickinson) or suppression of certain output that has already been generated.
3. Staggered output (credit here to Tom and Langdon); note that your tests may have failed because it conflicts with PHP/Apache's default internal buffer, but it is possible to do, it simply requires a certain amount to be flushed before PHP will send anything—PHP will still keep the connection open though.