NO it's not harder to understand. If you are doing anything remotely serious, then your php script needs to be on multiple servers for redundancy, it needs to be behind a load balancer, you have to be responsible for the security of the VMs the php script runs on, and on and on and on and on.
Edit: well, unless you run your php script in a PaaS like Google App Engine.
Edit: well, unless you run your php script in a PaaS like Google App Engine.