Some Phaser features do not seem to support canvas mode. Examples are using the alpha property with the graphics class. Also for some lighting features such as light2D. See link. I expect there are more.
My question is whether this is a problem for many of you? Like most I want/need my games to be playable by most if not all kids. I create educational games and would not want to exclude any students. Are there many instances now-a-days of devices and browsers people use that do not support WebGL? If so I will need to not use any of the nice features that do not support the CANVAS mode.