Now do the comparison if one endpoint is realtime user facing traffic and the other is batch processing which can easily eat up all available capacity and drive up latency.

If visa shoppers are overwhelming the normal processing of applicants who actually live in a particular country, it seems entirely appropriate to say "no, sorry, this location isn't for you" to the people who don't live there.

How about hiring more people? For that matter, why is the decision made in the local consulate or embassy anyway?

The whole worldwide visa system feels like a relic of the time before networks. Many tasks rely on physically moving pieces of paper around, leaving your passport with agents of a foreign government (!), and having documents that are stamped and supposedly authenticated. Shouldn’t everyone be able to separate the tasks of authenticating a person and authorizing that person to be somewhere?