I have some great pictures of Wishes. I took them with my digital camera.
I was standing behind the statue in the center part in front of the castle. I did not use the flash. Whenever you don't use the flash, you must hold the camera EXTREMELY still if you are not using a tripod. There is enough light in the fireworks to illumimate the castle for the photos. If you do use your flash, it will bounce off of the things it reaches first, like peoples heads and the statue. The fireworks will be in the background and most likely fuzzy.
It works the same with nighttime photos and the parade. In the dark, the flash will hit whatever it sees first and everything in the background will be fuzzy. If using the flash, the flash may hit the performer walking in front of you and the parade float will be blurry. But the motion of the parade and limited avaliable light may cause your pictures to be fuzzy no matter how still you hold the camera. With the parade, you may just be getting lucky. Your chances with the fireworks, being farther back, are better.
This principle of the flash at night is the same for both digital and 35mm cameras. But with a digital camera, you have to be more conscious about holding the camera still to get the picture because the pixels on the digital camera are so much smaller and susceptible to movement and there is less leeway that with the larger pixel grain on a 35 mm. (I think this is the technical reason for the difference).
I do have good photos from both events with my digital camera with no flash, so good luck!
P.S. When I took my Wishes pictures, I took off the backlight in my display so that my screen was black (as not to bother me or others around me) I held the camera up, and did not worry about looking at the display screen. I simply aimed and shot. (I practiced earlier in the day to know how high and where to stand) My camera uses a disk, so I shot the entire disk, and had another one ready to go. I did get very good pictures. One of them is my avatar.