If CBDC issuance coincides with banning physical cash, what makes you think that they won't enforce capital controls on alternative currencies?
The question is, will you live long enough to see the end of the ban. If you have children it may very well be worth it.
International trade is far too large these days to stop gold-smuggling.
Look at the great job we're doing with drug smuggling. Most cocaine enters the US hidden in shipping containers.