A machine polisher can be used on a vehicle for several reasons, including:

To restore shine to paintwork: A machine polisher can be used to remove light to moderate scratches and restore the shine to the paintwork on a vehicle.
To remove swirl marks: Machine polishers are especially effective at removing swirl marks and other surface defects, leaving the paintwork looking smooth and shiny.
To enhance protection: By removing surface contaminants and restoring shine, a machine polisher can help to enhance the protection of the paintwork, reducing the risk of further damage from the elements.
To save time: Compared to hand polishing, a machine polisher can save time and effort, as it requires less physical effort and can be more efficient in removing surface defects.
To achieve professional results: A machine polisher can be used to achieve professional-looking results, restoring the shine and protection to the paintwork on a vehicle, and making it look like new.

Overall, a machine polisher can be a valuable tool for maintaining the appearance and protection of the paintwork on a vehicle, restoring its shine and removing surface defects with ease.