Same reason as some browsers started to grey out parts of the hostname - if the only thing a user sees is "bankofamreica.com" or "bankofamerica.com.foroigs.io"

Same reason as some browsers started to grey out parts of the hostname - if the only thing a user sees is "bankofamreica.com" or "bankofamerica.com.foroigs.io" they have a better chance of catching the thing that's wrong. Noise/information ratio etc..