I run a local Valhalla build cluster to power the https://sidecar.clutch.engineering routing engine. The cluster runs daily and takes a significant amount of wall-clock time to build the entire planet. That's about 50% of my CI time; the other 50% is presubmits + App Store builds for Sidecar + CANStudio / ELMCheck.

Using GitHub actions to coordinate the Valhalla builds was a nice-to-have, but this is a deal-breaker for my pull request workflows.