Regarding pictures, they do take practice. The secret to taking pictures while driving is to figure out what works (camera mode, zoom level, position of the camera, and when to take it relative to the sign) and those things take practice. You'll have a lot of bad photos when you're learning. It will take time. But eventually you get there. Note that those of us who do take pictures while driving use the viewfinder only a little if at all. We don't spend lots of time staring at it to frame a shot.
And yes, a REAL camera is a must. Not a phone camera. Phone cameras don't deal with motion very well and require more concentration. Depending on how it's configured it may not even be possible to use with one hand (default is to take a picture by tapping on the screen). They don't have real zoom controls either, just poor quality digital zoom. Phone cameras also don't really have physical controls - to engage then, you HAVE to look at the screen. A real camera can be manipulated without looking at it at all, from memory. Many digital cameras also have an anti-blur mode that can smooth out the bumps.
Speaking of bumps, those are easier to anticipate while driving, for the same reason a driver is less likely to get motion sickness than a passenger. A driver is in control of the car, which means the brain can better anticipate what the motion of the car is going to be.