何故かこれは通る。{!Account.CreatedDate}と{!record.CreatedDate}が逆でもOK

sample.page

<apex:page standardController="Account" extensions="SampleExtension">
    <apex:outputField value="{!Account.CreatedDate}"/>
    <apex:outputText value="{0,date}">
        <apex:param value="{!record.CreatedDate}"/>
    </apex:outputText>
</apex:page>

SampleExtension.cls

public class SampleExtension {
    
    public Account record { get; private set; }
    
    public SampleExtension(ApexPages.StandardController controller) {
        record = (Account) controller.getRecord();
    }
    
}