Eh, I hate to say it, but this is probably the right move (if there's a switch to get it if you really want it, which other commenters are saying there is). Enough businesses are rapidly adopting "no GPT/Bard use in the workplace for IP/liability reasons" policies that it makes sense to default to opt-in for Workspaces accounts.
I don't care that it's opt-in. I care that it didn't tell me I could enable it and so assumed it was impossible. Also, perhaps it was not originally available? I don't know.
