The material carbon fiber is plenty strong to build a touring bike that'll be comparable to any steel tourer. The situation is carbon bicycles are primarily designed for racing and not specified for touring loads.

A carbon tourer for me means: carrying 202 lbs (me & 37 lbs gear & supplies) on all mixed terrain without worrying about a frame failure. Tour length needs to be measured in months not days. It should easily be counted on to do a full-on world tour

When I see a carbon frame that meets my criteria, I'm onboard. For now I'm not sure the 3-4 pounds of weight savings is worth the worry.

BTW: It's seems that there are 3d-printers spitting out carbon parts, so the day when we can order an affordable custom carbon touring frame is probably not too far off.