This has been suggested as one of the many reasons Bukele is so keen on Bitcoin/Chivo: he can't print USD, but having control of the national wallet system gives him countless avenues to manipulate the system.
Of course it could also allow the government to do worse things like backdoor wallets and confiscate crypto.
There are lots if wallets not registered with the El Salvador government, and it will be impossible for the government to distinguish those that are genuinely foreign from unregistered wallets used by people ot for purposes nominally subject to El Salvador’s laws.
So, no, it won't make tracking any easier, nor wil it make taxes and tariffs easier to enforce generally.