They are just two different solutions that have pros and cons just like any two solutions :) A few that jump out:

- Setup time: Setting up GCP, setting up a certificate, adding a static IP, etc. is not seamless/adds friction

- Autoscaling and rolling updates (no downtime)

- Team management and collaborative environment with usage tracking, permissions, etc.

- Optional integration with a pipelining service for training, tuning, deploying models in a single tool

And a point of clarification: Practically speaking, neither tool is free. Both require a cloud instance so they will cost roughly the same for the end user (Gradient also supports preemptible instances).