It helps to expand the gene pool of specialized breeds if you seek mates internationally. This is necessary to continue to select for desired traits without resorting to inbreeding or drastically reducing the amount of breeding that's done.
"Specialized breeders" have zero sympathy from me; the only reason they have problems with their gene pool size is because of their own stupid breeding habits and objectives. Go get a mutt from the pound if you need to expand the gene pool of your dogs. The reason German Shepards in America are fucked up is not because import of dogs from Germany is banned, it's because American breeders of German Shepards are fucking idiots [generally speaking.]
The main reason to allow dog imports is probably to accommodate people relocating or returning to the US.
As a matter of fact, though, the reason the ban has been introduced has been a consequence of a dog shortage. Because many people are spending more time at home alone, demands for pets has gone up. Apparently there aren't enough dogs in the US to fulfill current demand.
There are millions of dogs waiting to be adopted, It is not about shortage of dogs but some rescues specially importing stray dogs from other countries.
Just go on petfinder and see how many dogs are available
I tried for months to adopt a dog -- none of the dogs I applied for were available for adoption the moment I submitted the application. Not sure if it was my luck, but after 20 applications I gave up.