So there's an opt-out.
The article seems concerned that the email announcing this doesn't include a specific path to the opt-out right in the email (which is a weird concern, considering the email provides two links to... presumably that information)?
I'm not sure what this means, either, but it seems the "whether your Gemini Apps Activity is on or off" line is saying that you can still have Gemini send texts for you even if you disable Google storing your apps usage server-side? I don't use Gemini as an assistant, so I'm not sure, but looking at the Gemini settings menu on my Android phone that's what it seems to map to.