In fact, not just Oracle to Postgres migrations, but any time we think of putting business logic into an Open Source Database, I think PostgreSQL is the best of the choices we have. We always think Oracle and SQL Server are the only best options we have. In fact, PostgreSQL does a great job in handling Stored Procs. One such plprofiler like tools makes more difference for developers.
There seems to be quite a lot in common between PG and Oracle RDBMS, PG is the database that seems to make the most sense to me as an ex-Oracle RDBMS person? So I can see how this functionality could be a blessing in a migration project. Time to roll up my sleeves and study postgres I think...
And from PostgreSQL 11, it supporting transactions within Stored Procs is killing. Earlier, Oracle to PostgreSQL required developers to re-write a lot of logic in application to make it for PostgreSQL. Now, from PG 11, it supports transactions and that made the migrations more and more easier.