I think it's good to hear someone talking about it. I've never used it - perhaps I have the impression that it's not even something I could just go sign up for with a credit card and start using as a non-business entity.
But, I see things like https://github.com/IBM-Cloud/terraform-provider-ibm exist, so it must be at least reasonably usable.
What's a reason why someone would consider this over the big three, besides sweetheart deals for big customers?