When is low latency important?

You ideally want a lower latency in real-time services that rely on fast use inputs. Some examples are:

• Video chat: With a higher latency, the caller on the other end will receive your reply later than usual and vice versa. This could cause attendees in the chat to speak over each other or long awkward pauses.
• Online Trading: Online traders need to have as low a latency as possible due to their buy/sell orders needing to be submitted as fast as possible. With high latency, the trade information will be delayed in reaching the stock exchange and could result in higher losses or lower profits.
• Online gaming: In gaming, you would want a low latency as possible. With a higher latency, the time your character responds and updates from the online world is shown to your screen, is slower. This causes a delayed reaction between your input actions and the responses on the screen.