SST has no dependency on SEED for deployments. You could configure a custom build process on a CI/CD service of your choosing.
The reasons to choose SEED instead of other providers are as follows:
1. To support an organisation financially and socially that made something like SST.
2. SST projects, under certain limits, build for free on SEED.
3. SEED just raised $1M in funding.
4. SEED has features to monitor your lambdas and report issues to you via emails/slack.
5. Since, SEED is a small group of very talented people and not an enterprise their development decisions won’t be marred by business decisions. I am hoping that this would stay the same even when SEED goes big.
These points are valid enough for me to trust SEED and rely on SST that’s open source.