Controlling area type Currency 30 or 40

Hi experts,

In the next scenary, wich type currency do you recommend to use:

Scenary

• 10 company codes in three different countries with different local currencies
• The hard currency of three is USD.

I should configure:

1° OPTION

• Company code -
  • 1st local currency: 
    • Currency Type:  10 Company code currency
    • Currency: the corresponding with the country
      
  • 2nd local currency: 
    • Currency Type:  40 Hard Currency
    • Currency: USD
      
• Controlling area - Currency Type: 40 Hard Currency

2° OPTION

• Company code -
  • 1st local currency: 
    • Currency Type:  10 Company code currency
    • Currency:  the corresponding with the country
      
  • 2nd local currency: 
    • Currency Type:  30 Group Currency
    • Currency: USD
      
• Controlling area - Currency Type: 30 Group Currency

Which option is better, and why?

Thanks in advance for your help.

Regards,

José Luis