PHP is not perfectly fine as a procedural language. There are several important features missing, like Function autoloading, without it you need to come up wit

PHP is not perfectly fine as a procedural language. There are several important features missing, like Function autoloading, without it you need to come up with a reliable way to require dependencies. This usually differs from project to project in a non-reliable way and will be messy if you don’t think this thru. It will also affect things like testing. Only global state or (closed) function state. Namespaces are fake in PHP, it only adds the namespace name to the class name or function name, you can’t store anything inside a namespace like in C++. Thus everything is global, which is horrible and bug prone. You can use static inside a function to keep state as an alternative, but that is hard to manipulate from the outside when needed. It can be done with a separate function that keeps track on other functions state. When I tested modern pure procedural that is what I did. No typedef for function signatures. If you want to create a contract enforced by the compiler you use interfaces in OOP, in procedural you want to define function signatures instead, but there is no reliable way to do that in PHP without classes (ignoring any external tooling that uses phpdoc) Testing. Have you loaded a function into the runtime you can’t unload it again, thus mocking a function you already tested becomes impossible. You can solve this by running every test unit in a separate PHP process, but that is expensive. These are the biggest and none of them will probably never be fixed, perhaps function typedefs has the biggest chance but I doubt it. If you are writing a large project (+500k lines) all of these are very important. That is why OOP PHP rules because it can handle all of this. The problem with OOP is that many of the legacy OOP projects inherited the inheritance based OOP from Java, however today we know that composition based OOP is better (both in Java and PHP).