IIRC I was there last year, and the temp lounge on the left as you head down was accepting of either Diners Club or Amex customers, cant recall which now. But I only discovered this as I was about to board. Had a peak in, and didnt seem too exciting.
Not a whole lot of other options after coming through passport control, so with the exception of avoiding long lines at security, I would hang out in the main terminal as long as possible if I were to go again. Unless the temp lounge is gone and something a little better was available