Why realize all deferred elements at OnApplyTemplate?

[nxtn-staged]

Take PersonPicture as an example. I noticed that x:DeferLoadStrategy="Lazy" is extensively used in XAML but all deferred elements are loaded by GetTemplateChildT at OnApplyTemplate. I assume x:DeferLoadStrategy="Lazy" doesn't make too much sense then.

According to x:DeferLoadStrategy attribute, calling GetTemplateChild realizes deferred elements.