18v or 20v battery which is better? EP 8

Doubt to buy battery powered tools, what is the difference between 18V and 20V batteries, Bosch batteries are 18V (18 volts), and what is the difference to 20V batteries (20 volts) advertised by competitors, watch this video and understand what changes to make the best decision when buying your battery-powered tool, you will see that Bosch is your best