Modern launch monitors work to a high level of accuracy however there are margins for error. Trackman for example say that they measure the full trajectory of every shot from a 6 foot chip to a 400 yard drive and is accurate to 1 foot over 100 yards.

Are launch monitors worth it?

It's a price point that doesn't make it an accessible option for the average golfer — unless you have deep pockets. For the best golfers on the planet, the launch monitor can be an invaluable resource. It spits out real-time data (ball speed, launch angle, spin, carry, clubhead speed, path, angle of attack, etc.)

Are golf launch monitors accurate?

Yes, sophisticated and the best golf launch monitors are incredibly accurate. Since these monitors take measurements of several different data points such as swing and ball speed, you can find a precise reading of your distance and other factors that help create distance and determine accuracy.