By using this, we will save time and can gather all the snippet into one template, if else will help much.

But that's only in the case of simple template and layout. When a templates is too different from the layout or custom fields (using the advanced custom field, maybe), it would be hard to customize and making everything look exactly as design (or HTML template).

So I think it's just the first step only of bringing multiple template tag into WordPress, what I'm actually thinking is, WordPress in future will have the ability to create custom fields, view, and relation between fields, views, types (CPT) in the right your admin, it would look like Odoo (openERP) is doing