Why duplicate records in yml?

[asolntsev]

Hi @stympy

Can I ask why Faker has duplicated records in some "*.yml" files?
For example, from the very early commits file en.yml has this block:

  name:
    formats:
      - [:prefix, :first_name, :last_name]
      - [:first_name, :last_name, :suffix]
      - [:first_name, :last_name]
      - [:first_name, :last_name]
      - [:first_name, :last_name]
      - [:first_name, :last_name]

Why this line is duplicated?

[stympy]

The idea was to weight the responses... The [:first_name, :last_name] combo is more likely to show up in results than the other two because it appears in the formats list 4 times more than the other two.

[asolntsev]

Thank you. The goal is clear.
The only concern is:

1. Why it's needed to weight the responses? Why it's a good idea? For example, if I generate test data, then I rather prefer corner cases to the "typical" data.
2. Why this is applied only for names? E.g. why not for addresses? Like, "Main street" is more popular than "McClane street".