Understanding some flutter design decisions - flutter

Question

Apologies if this question doesn't belong here but some flutter design choices seem unintuitive to me and if you all could help me in understanding why it's done like this, I feel I would have a better grasp of this framework.
Also, I come from a webdev background, therefore CSS type styling makes sense to me so that could be another reason why this type of styling seems so different.
I haven't done a lot of flutter but from my limited experience I have the following questions:
(I realize that some of it may not be optimal and hence the reasons for my confusion might be me just doing it incorrectly, in which case please do correct me)
This is the code I wrote for changing the background color of a button
TextButton(
child: Text('Example'),
onPressed: onPressedFunction,
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all<Color>(Colors.SomeMaterialColor)
)
)
or alternatively
TextButton(
child: Text('Example'),
onPressed: onPressedFunction,
style: TextButton.styleFrom(backgroundColor: Colors.SomeMaterialColor),
)
Q1 Why do I have to specify that the style will be of type ButtonStyle(....), any style that goes into the button class should be of type ButtonStyle right?
Q2 The reason why setting backgroundColor isn't as straightforward as backgroundColor: CustomColor is because "backgroundColor isn't Colortype, so you can't use Colors.YourColor" , but why not? what advantage do you get by not making it ColorType
When changing the theme of the app, this is the code that I wrote
theme: ThemeData(
colorScheme: ColorScheme.fromSwatch(
primarySwatch: Colors.red,
).copyWith(
secondary: Colors.purple,
),
),
Q3. Using fromSwatch and copyWith seems convoluted, why isn't it something as simple as
ThemeData(
colorScheme: ColorsSchemeClass(
primarySwatch: Colors.red,
secondaryColor: Colors.purple,
),
)
I am sure there are excellent reasons for this type of design but I can't seem to understand them, therefore any help would be greatly appreciated.

Answer 1

First of all It's all depending on what is called Material Design by Google. It has certain guidelines that must be followed to achieve maximum Flutter theming advantage.
Q1: Dart is hard-type language in general. And the use cases is different form widget to another, with some similarities. for example Button style has on hover color or splash color. while Text doesn't need this property. But both of them has foreground color.
Q2: As I mentioned before, Material Design is essential for the Widget that flutter provide. you can make your custom widget the can take Colors directly but I would not recommend this approach.
Q3:In Material Design concept, There is two main type of colors, Primary and accent colors, That's makes Flutter deal with Color Swatch. For your example First create red color swatch and copy it's property with changing the secondary color to purple.
For more information with Material Design in general read this
link
How to implement it in flutter read this article