Why magento2 use UI components in Recent release of magento2,1[product edit page]?

Question

In recent version of magento (Magento2.1), they have totally changed structure of product edit page (Backend). I mean they had replaced with UI components.(While in previous version of magento2.X they are not using UI components.)

Is there any reason for that ? If yes, then why they didn't addded in previous version of magento2.x ?

Answer 1

Magento 2 is slowly moving from form and grid blocks to ui components for all the entities in the admin (at least that's the intention).

Some of the entities are already migrated, some are not.
They are doing this gradually.

In the previous versions of M2, the forms ware migrated from m1 and used the same approach (form blocks, grid blocks).

That's why you saw that product form in previous versions.
I guess the time has come for the product form to move to ui components.