God morning ( evening ? ),
Why choosing aluminium vs CF ?
The CF is very very stiff and it could be a problem when you are hunting vibrations. In CF the vibrations are very well transmitted longitudinaly along of the carbon fiber.
Another problem is in case of crash: if you crash the frame in the direction of the carbon fiber, it wil transmit all the energy along the fiberdu to the stifness. It's rare but when it happens, you will break what is clamped at the end of this part (generaly center plate or electronics).
Final point: the CF is very costy and I don't think I will find lots of people that will want to buy a 800 or 900€ frame (I'm not as famous as Droidworks
)
I still have to do vibrations tests on my frames bt I'm sure it's pretty good