Originally Posted by Camilo

Oh yeah, I would think that disc brakes with QR hubs would be a good reason to use the internal cam QRs if there wasn't adequate clamping force with the external ones. I have never owned one (my one and only is thru axle). I just speak from regular rim brake bikes with vertical dropouts front and rear. There's no real force on the QRs requiring exceptional clamping force, and the external ones work fine. Older bikes with horizontal rear drop outs definitely need them because the rear wheel tends to get pulled forward by the chain on the drive side. On my current vintage bike, I not only have to use genuine Campagnolo QRs, I have to force them closed with all my might - and they're tough to release! Couldn't get it with any external QR I tried.