R12.2.5 Budget Currency

What are adv and disadv of maintaining all budgets for all the ledgers in one ledger?

We have US and CAN ledger - can we maintain all the budgets in US Ledger ?

If we maintain CAN ledger in US ledger - we will enter the budget in CAD currency - will the system convert the budget in USD currency since we are entering the budget in US leger?

IF so, where is the converted amount stored ?

Will entering all the budgets in one ledger impact the comparison with actuals ?

Thks