The part that casually drops "PHP as a config language" is where this jumped the shark for me. I guess this isn't the worst practice I've seen in PHP, but it's definitely a notable one.
and in that context, it is perfectly reasonable, I think.
what issues do you have with the idea exactly?
I certainly don't think that the web server should be writing out executable php scripts, if that is what you are asking?
OTOH, I have seen many examples of php configuration files done by simply setting values in an array, looking up other values from other places and so forth - i.e., an executable configuration file written in php.
I think it is a bit of a jump though to assume that the author was suggesting that the web server be able to write executable php files?