[sebe]

I think the sub second hot reload feature, makes it cool. Have a look at the "Unified layout" section in https://hackernoon.com/why-flutter-uses-dart-dd635a054ebf and or install the flutter plugin in vs code or android studio and have a play.

[pjmlp]

Makes it cool, but nothing out of the ordinary for anyone used to other native GUI development tools, like the ones I referred to.

Here is Interface Builder in 1986, https://paulhammant.com/2013/03/28/interface-builders-altern...