This exchange is not unpopular per se, it is within the top 40 according to Coingecko, and their volume is not so bad either. As far as I can remember, their most important product is the Piggy for staking since the funds are insured. I personally know some whales are using their services to stake coins, but can't say more than that.
I think I'd not use them if I just want to trade, since Binance and other top exchanges have way more volume than Bitrue.
ill never use that exchange but having that many scam accusation is already a red flag for any exchange.
How many are the accusations? I don't see OP even mentions the number of it.