Yes they are beautiful. Moreso, they are turbulent.
Two weeks ago a child, approximately 6, asked me why we didn't fly through these clouds on our flight. This was after saying he loved flying but was "scared when it was bumpy." I had to explain to him that the clouds are what makes it bumpy and that it would have been bumpier if we had flown through them. Sadly, he left dissatisfied with my answer.
In reality, the puffier the cloud, the more bumpy it will be to fly through. The puffiness is a result of the rising air currents moving at different speeds as the warmer air ascends through colder. This rising of air creates the worst of the turbulence.