First of all, I must say that Okex is not my favorite exchange, but I use it to sell coins and tokens that are not listed on other exchanges. I also participated in an options trading simulation and got a good amount in BTC.
I prefer fully regulated exchanges like Coinbase or Liquid because I trust the exchange to only have a regulator that meets the security standards.
However, I use OKEX to sell smaller coins and tokens.
They have a good community, great managers, and good support. If there is a problem, Telegram administrators will do their best to help you.
At the same time, they are developing very fast, they already offer sensitive transactions and options trading, which is a huge advantage over other exchanges.