What are the performance implications of using uuid as primary key in Postgres 10.12? (need canonical answer)
It is easy enough to benchmark this, but the INSERT performance of UUIDs will be worse, because they are bigger and slower to generate.
But it doesn't sound like you are building a high performance application anyway (then you probably wouldn't be using JSON), so it probably won't make much difference.
Finally, you want to use UUIDs for security reasons (which I won't discuss here). Security always puts a penalty on performance and usability, so consider it as the price you are paying for security.