Binance is doing leverage ? Or speculators leveraged the bounce on Binance (still not really delisted until the 20 Feb). These people (if they can be reached) should more be advised to trade in spot, on places where they can actually withdraw funds to use them.
Well, I know local Monero has a data API, so the price could be tracked. Often, on local Monero, you’ll find a minimum of a 10% markup on the XMR/USD pair. That comes down quite a bit if you get something like USDC or USDT though. My guess is primarily that is due to a lack of sellers pushing down rates and to the fact that payment methods straight from fiat can be reversed.