On a personal level, the successful development of such a test would help people all over the world recover faster from bacterial infections.
It could also help reduce burdens on healthcare systems by ensuring care and treatment are prompt and effective, preventing or cutting the time of hospital stays, and making targeted antibiotic prescribing available in more settings like pharmacies. This would also cut countries' healthcare costs by reducing hospitalisation and hospital stay lengths, and reduce prescription costs by removing the need for ‘trial and error’ antibiotic prescribing and ending antibiotic prescriptions to people with viral infections.
On a global scale, making sure antibiotics are only prescribed when they are needed and when they will be effective could slow the process of bacteria developing the ability to defeat the drugs designed to cure them. This will preserve the effectiveness of the antibiotics we have, meaning they will work for everyone for longer, creating a healthier world and buying us time to develop new antibiotics.