"If you're used to servers written in interpreted languages (or named after precious gems), prepare to be pleasantly surprised by PostgREST performance."

then

"Ultimately the server (when load balanced) is constrained by database performance. This may make it inappropriate for very large traffic load."

ROFL. Bragging about performance, then "but don't use it for anything big". So instead of getting a solution which scales out with app servers in the "language named after precious gems" (straightforward), you get to scale out Postgres servers (not straightforward).