Oxo-degradable products are still sourced from fossil fuel based resources, they will also take a significantly longer time to break down I comparsion to Compostable Bio-plastics.  Unfortunately there has not been conclusive evidence for the complete breakdown of oxo-degradable plastics or the types of residual compounds released in this process. Where as certified compostable products have gone under this rigorous testing.

https://www.bioplastics.org.au/150-organisations-worldwide-back-ellen-macarthur-call-ban-oxo-degradable-plastic-packaging/

https://www.bioplastics.org.au/wp-content/uploads/2017/06/The-Impact-of-the-Use-of-Oxo-degrdable-Plastic-on-the-Environment-For-the-European-Commission-DG-Environment.pdf