Credit cards are a must, especially in Qatar. It will help you pay online, hassle free, your phone, internet, electricity & water bills, Metrash2 visa, RP, Driving license fees. Etc. This comes after owning a CC for 8 years in Qatar. Especially with the much cheaper merchandise that is purchased from amazon, eBay, aliexpress etc. since the market here is very expensive.

Concerning the hidden charges that's being discussed, as long as you return the amount owned before the end of the month, you are not subject to interest. I have a Doha Bank card, set to 10% repayment, I usually return 100% of my expenditures to avoid such interest.

It's ultimately your choice, in the end, whether to get one or not. But if you don't get one, don't be that a**hole begging your colleague so buy you something online or pay you your bill. That's the major downside of it anyways, Beggars.