>when your application starts scaling across many instances, many zones, many servers, you can have more faith that each request runs independently and there ar

>when your application starts scaling across many instances, many zones, many servers, you can have more faith that each request runs independently and there are no runaway processes to worry about on a single one of your random servers somewhere It's just as easy to scale with other languages, you would keep the data that needs to be persisted in a DB. The benefit comes from things that does not need to be persisted, like resource pooling, memoization, config loading etc. > > where I'd almost have to visit every branch of code when I alter something because of it's many weird behaviours >Write a method, write tests for that method Exactly, I need to write tests for things that are trivially verifiable by a compiler. And I'm not just talking about type coercion (which is a bad thing), but also missing function parameters, wrong parameters, missing initialization of variables etc etc. These are runtime errors and you either have to write tests to catch them (hence visit very code block) or manually try and reach them. Some IDEs, like PHPStorm, can you get pretty far though. >Low barrier to entry gets you a lot of crummy projects As someone else mentioned in another comment, 1% of PHP projects succeeding is still a lot more than 20% of Haskell projects. >PHP is a lot easier to manage and maintain in production Except for when you need to scale. Varnish, memcache, php-fpm, redis, what-have-you are basically mandatory for a PHP site to really run performant, adding quite an overhead to any production setup you'll get into.