It seems like it is possible to control aspect of playing the game with only the mouse except waiting can only be done by pressing space bar. It would be really nice if waiting a turn could also be done with the mouse. Either by clicking on the player character with the left or right mouse button to wait one turn or wit an on screen button like the inventory and character screens.
The mousewheel/middle mouse button could be a good idea. Although some people may not have one. I, for instance, use a trackball that unfortunately has a non functioning scroll wheel. I wasn't aware that there was a "digest" command. Not sure what you mean by that. Clicking on the same tile that the player is standing seems logical. I actually assumed that clicking on the player would wait one turn when I first started playing.
The digest button on the bottom left? if you have food it rests instantly until your food is done digesting. But if it was made so clicking it also skips a turn then it would be multipurpose