The job on paper is great: flexible work, flexible pay and flexible in location.
The company does not care for you and uses the riders as a scapegoat for any issues, similarly the restaurants do the same.
Deliveroo cultivates an environment of constant pressure and job threat.
This environment pushes you to work in the most dangerous conditions, and to ride at the edge of your limits safety wise, to be able to make enough deliveries to make it financially viable.
The 'illegal workers' issue has arisen because of a loophole that the company keeps specifically open to keep riders self-employed from a legal standpoint, so they can avoid having to accommodate for rights that other employment statuses would have.
After using the environmental bicycle image to market themselves, they have been systematically pushing out bicycles in favour of anything with a motor.
A great job, as long as you are aware of who you are working for, and are careful to log enough evidence to protect your job.