This article is pure FUD with lies.

1) The spread is not "plus or minus $500", it's a lot less. See for yourself:

http://bitcoinity.org/markets/bitstamp/USD

At this particular moment the spread is $23 on Bitstamp, zero on GDAX, $11 on Bitfinex, zero on Kraken, zero on it it (where "zero" is something under a dollar, there's not enough precision to display it).

2) Yes, you can cash out, a lot. There are dozens of huge exchanges where the daily volume is in billions.

https://coinmarketcap.com/currencies/bitcoin/#markets

For instance, Bitfinex USD/BTC 24-hr volume is $1.2 billion.

And that's just one currency pair on one exchange.