The fact is most poker bots are not great at poker. Yes, they're winning players, but just barely. A bot's real value comes from the volume of poker it can play. But that volume can easily go unnoticed.
Yes and many people do. It's risky though because you can also lose money too. Many big poker sites these days have anti-bot detection software but they're not particularly effective. The best way to find bots is when many different players flag a player that they think is a bot.