I failed my first try because a guy in a BMW didn't wait until I pass before he turned left and I waited - they said I was too unsure and thus failed.
Same experience with the speed target/limit in the Czech republic.
Sure but if you have had 40 hours training you know to slow down when you see a bend and not to continue at the target speed. Hell if you've had zero hours training but have been in a car before you know that.
Please be aware that the rather strict driving test in the Netherlands means that you are trained for at least 40 odd hours, or let's call it 60 hours on average, to drive at the speed target. Going too slow means you're unable to handle the traffic, and going too fast is illegal, so this strictness can instruct people to drive at the speed target.
Yes, I did name them targets, because that's what they're used for. It looks like a target, it acts like a target, it's called a target. Legally, they're limits, but I don't think you'll ever see many people driving at the limit. Always at least 1 or 2 km/h faster.