This is from the Economist:
Where some see an anchor, others see a millstone. To maintain the euro peg, notes Ndongo Samba Sylla, a Senegalese economist, these very poor countries must track the hawkish monetary policy of the European Central Bank. Since the introduction of the euro, income per person in the franc zone has grown at 1.4% a year, compared with 2.5% in all of sub-Saharan Africa.
People like Cameroonian president Paul Biya love the CFA. With good reason.
Yet elites do rather well out of the system, which makes it easier to send wealth abroad. And a weaker currency would increase the cost of imported goods. The only devaluation, in 1994, sparked riots.