Do you feel the use of the Euro would be beneficial for the members of NAFTA?

No.  That would require all NAFTA members to handle transactions in a
currency that is not the national currency of any one of them.  One
might argue that this creates a more level playing field instead of
having the US dollar the leading currency in NAFTA, but it would just
unnecessarily complicate transactions and make them more expensive
since foreign exchange transactions would be require for every
settlement, in most cases, two;  the buyer would have to buy Euros and
then the seller would have to sell them, whereby major companies
(primarily US ones) might have an advantage if their European
operations allowed them to use Euros from or for these activities and
thus avoid the foreign exchange transaction.