If you hit it big, you’ll spend on their platform for a long time. You don’t have to explicitly promise anything because you’ve built everything around their platform for months/years.

Moving clouds is hard if you use the cloud features. Giving credits to startups is a cheap way to get them locked in for the future.

If you have enough funds, you might not care about building an efficient architecture, and when the credits run out, you’ll spend more?

Also good PR.

Your future spend. Once you start using them, it would be a decent amount of work to change.

probably vendor lock in

my understanding is that GCP has recently changed their startup programme. I applied a few weeks ago, and had the same bad service as the OP.