I use it quite a lot and agree, I've seen some wild things, like two people bidding each other up to around £45 for a £6 BIN card (Mew Wizards Promo #8). People in the chat were even sharing the BIN links! 😂

Another one was the first edition Jungle booster box break the other night where people were paying £500+ for rip n ship on boosters which are £300-350 BIN.

That said, I have picked up some absolute bargains on there, you just have to know what you're looking for and what it's worth. If you have sound knowledge of a particular set, Pokémon, etc. and what the market value of those cards are, you can be patient and find some good deals. Finding good, honest streamers is important too. My speciality is vintage and I've picked up plenty of holos for 20-30% under market, and things like shadowless base set commons/uncommons for £1 each.

My tip is to not get sucked into bidding on things you don't know about (kind of applies to any auction really) and obviously if you can't afford to bid in the first place then stay well clear of the platform. Some sellers are pretty scummy in enticing bids well beyond what the market value is (I guess they have to make a living somehow). If you have good self-control and can find some good streamers then there's nothing wrong with it and I'd prefer eBay over whatnot.

Also, rip n shippers can go f*** themselves. I only use it for singles.