This feature where external URLs are created dynamically, where certain parts of the URL are dependent on values defined in other blocks, would be extremely helpful while using templates. For example, I have a property called url in my template, which I would update in all my template applied blocks. However, I want a block with iframe, which gets substituted by the url defined by me. In certain templates, I would want to partially fill a URL even.
I’m only specifying my use case here and this feature need not be limited to that.