Some use it to level characters or farm materials
And leveled accounts can be sold

Not everyone plays MMOs for the pure fun of it. Have you ever heard the term "gold selling" or "gold trading"? It's related.

Gold selling/trading is a banned practice in most MMOs where someone makes a bunch of gold on a character, then arranges to sell that gold to other players for real money. It's a huge no-no in just about any multiplayer game, because it ruins the economy and usually involves the use of bots.

Bots can automate tasks that some players find very repetitive and can be left to run 24 hours a day. Things like farming certain items en masse or farming rare drops, for example. Bots allow gold traders to set up a bot to do this, leave them to run 24/7, and then sell their loot at low prices (again, borking up the economy) to still get massive profit for literally no effort. Then, they sell the gold they made for real money in deals arranged outside the game. It's super shady, drags down the in-game economy, and is one of the big reason why bots aggravate so many players.

So yeah. Bots are bad. Report them when you see them.

EDIT: And in ZOS' defense, they do do things about bots... it's just hard to tell. Reporting them sends data to ZOS, who collect that data to not only ban individual bots, but to figure out how the bots are working and ways to counteract it. Every few months, there will be a huge bot purge when they enact something to stop the current bots from functioning. Then, the botters find a way around those measures and slowly start trickling back in until ZOS enacts the next counter-measure. It's basically an arms race.

Thank you everyone for the comments. I understand now. So people would buy the accounts or gold. So they are taking short cuts then. I never knew you could do this. I guess playing Fallout and TES games single player only and this is my real first MMO, I just didn't know about them.

Again thank you for explaining it.