That's true, but when I said decoupling I meant "break the common misconception that one cannot happen without the other". It's more about breaking the idea than actually separating them. I don't think we can introduce Basic Income as a full income directly anyway, it will most certainly be gradual (start with e.g. a BI equal to the level of poverty, and go up from there)... but the most important part will be achieved: people will stop thinking that in order to live there is no other way but work, even in useless jobs.
It should be noted that BI is a partial decoupling of revenue from work, not a full decoupling.