I bought my wife a compound bow - gave it to her for Christmas one morning. Took it out that afternoon and we got it sighted in. She had never drawn a bow in her life. She was about 50 yrs old at the time. She took it hunting the next afternoon and killed a doe. First deer she ever shot at with a bow. These new compounds are pretty dang easy to shoot. Granted, a beginner isnt going to shoot one inch groups at 20 yards with a compound - but three inch groups are easy and lethal at 20 yards.
I agree with Catscratch - for most deer hunting in my area, shots are 30 yards and in. Many years, after not shooting my compound bow for six months, I would pick it up a month before bow season, walk out on the front porch, and shoot my first arrow of the year at the target 60 yards away. Usually, it was in the kill zone. I needed almost no practice to be dead on out to 30 yards with my compound. Now when we would go out west, it took a lot more practice to be efficient out to 60 yards. THe last 15 years I hunted with a compound, I didnt ever feel like I was going to miss if the deer was within 30 yards - and didnt. The biggest thing for me was shooting a ton of hogs and learning patience - waiting for the deer to turn to a good position for shooting. When I was younger, I was pretty prone to take a risky shot.
The biggest difference I see in a compound and a crossbow - is you dont have to draw a crossbow - making it harder for a deer to detect you and allowing a hunter to hunt effectively in many locations where hunting with a compound would be ineffective. A crossbow Also allows young kids to effectively kill deer that would not be able to hunt with a compound. Most of my grand daughters killed their first deer at age six or seven with a crossbow. Of course, they probably would have killed their first deer with a rifle one month later.