For another thing, the Internet has somewhere in the neighborhood of two decades worth of traffic bot programs littering the digital ground. Some have gone through upwards of a dozen name changes and rebrands, moving from one site to another. They disappear, leaving existing users in the lurch, never to receive support or updates when the program stops working. Then identical software comes out under a new name, charging anywhere from $5 to $250, scamming people out of their cash with the same back-end software.
Not all web traffic is welcomed. Some companies offer advertising schemes that, in return for increased web traffic (visitors), pay for screen space on the site. There is also "fake traffic", which is bot traffic generated by a third party. This type of traffic can damage a website's reputation, its visibility on Google, and overall domain authority.