It is very easy to have a play with a benefits calculator to find out what reality looks like for yourself.
In-work benefits keep working people who earn less than they need to survive at or slightly above the poverty level. For people who are unable to work, due to sickness, disability or a lack of available jobs, it keeps them stuck below the poverty level with just about enough to survive but not to thrive.
As the article points out, the philosophy this system was built on was not necessarily well thought out at the time. In the post-covid era it is disastrous.