[Qusetion] Bootstrapper or App.g.i.cs change.. What's better?

[Bantree96]

Please understand that I used a translator because I am not familiar with English.

If you look at the example, there are two ways to use "Bootstrapper" and to change "App.g.i.cs", which is the better way? And I would appreciate it if you could explain the difference between the two.

thank you.