I have a suspicion most of these types of agent-targeted SaaS will die out once the human equivalents implement their agent layers / MCPs.
Agents having no way to pay for their use is one thing; lack of deep integration within the business domain is another (e.g. if you're a Git provider, you'd probably want to offer CI/CD, PR workflows, release management, publicly discoverable repos etc., and boom - you just copied GitHub)
There's probably still going to be a box of hard drives in a datacenter somewhere, it does make sense to have a layer to manage the agent interface, rather than letting agents completely loose on all your storage.