This is hostile to end users, small people an companies, not just big megacorps wanting the "steal" the code and run it as a service. Be successful in running and using Hashicorp's software, and they decide to shut you down if you are deemed a competitor.
Like https://github.com/hashicorp/vault/blob/main/go.mod#L25
Yep open source is used as a marketing. I doubt they'd gain much adoption if it started with BSL at first place.
Adoption is one risk, https://github.com/hashicorp/terraform/graphs/contributors is an entirely different risk
I don't have the emotional energy to dig up such a report, but I'd be stunned if Sentry receives the same outside contribution rate as it did before
At any moment for any reason they can declare that you your use or your business in some way competes with them and cut you off.
You have no recourse. They don't need to explain it. They can even add a product remotely like what you're building or misunderstand your product and you are screwed.
The BSL carries with it immense legal risk.