Why in 33:56 Allah SWT, instead of himself saying directly, is ordering to the holy Prophet SAW to tell the women of the believers?

Why in 33:56 Allah SWT, instead of himself **telling it directly (meaning addressing to us)**, is ordering to the holy Prophet SAW to tell the women of the believers to bring down over themselves [part] of their outer garments? **Does this mean that Allah SWT wants this (bringing down over themselves [part] of their outer garments) to be a Sunnah rather than Fard?** The verse : > O Prophet, **tell** your wives and your daughters and **the women of > the believers to bring down over themselves [part] of their outer > garments**. That is more suitable that they will be known and not be > abused. And ever is Allah Forgiving and Merciful.