No! VPNs have a multitude of use cases, which is why so many people around the world use them. For example, although VPNs sow your connection down marginally when you turn them on, they can speed up your connection if your internet service provider is currently throttling your bandwidth, which may be happening if you perform a lot of data-intensive tasks like playing videogames and you're noticing a significant slow down in connection times. With a VPN, your internet service provider can't see what you're doing whilst online, so they won't know how data-intensive your traffic is. There are plenty of other use cases too.