Please highlight how this is too broad and/ or could be made to go your way. I've pointed to such issues with Apple App Store ID's and accounts and widely written about issues with them. There's many articles on that subject but not much about Amazon accounts.
What are Pros & cons of using Login ID w same email address or different ones, when having Amazon accounts in multiple regions US, UK, India etc
The above was used both on the question title and body. It makes the question too broad because it encompases two scenarios:
same email address or different ones
Also it also encompases a broad list of countries
multiple regions US, UK, India etc.
By the other hand, including links to questions on Ask Different SE, regardless that they have a 0 score and answers with low score doesn't make the question specific and on-topic on Web Applications.
Questions should include on themselves all the required information to respond the question.
The question doesn't mention if you already have Amazon accounts in multiple regions nor if you already faced a specific problem.