Polishing concrete produces a lot of hazardous dust, and you have your choice of wet and dry options to control this.
Wet polishing is usually faster and produces good results, but also produces a lot of toxic slurries that you need to store and dispose of correctly. Professionals have the equipment to handle this, but it can be harder for homeowners and tool renters to manage.
Dry polishing is slower and produces a lot of dust, requiring a HEPA vacuum to suck in dangerous particles floating in the air. However, it’s also easier for most people, and dry polishing produces better results at 1500 and 3000 grit. Some people use wet polishing for the earlier levels, then switch to dry polishing at the end.
In short, both are viable options. However, if you can only choose one, do dry polishing.