Right but it is cheaper than open source products if you self-host. Most open source products in this space, including grist, are only partially open source.

[grist employee here] Grist forms are open source and were used to keep the toilets clean at FOSDEM just a few days ago https://fosstodon.org/@grist/116001932837956733

Everything you see in our standard docker image is open source. Yes, you can enable and pay for enterprise features too.

It is weird that your enterprise features are not self-hostable even if a customer pays. I understand if some features are not open source, but why make it not self-hostable? Self-hosting is a requirement for confidential data.

The enterprise features are self-hostable. Look at "your servers" on the pricing page for Grist. Individuals (and orgs with < $1 million in annual income) quality for free activation keys btw.