The advantage of the tadpole configuration (two wheels in front) is you can brake hard while turning without rolling over. For use on the road, having functional brakes outweighs any other advantage the delta configuration may have.
This does not mean the tadpole configuration is perfect. I own a Trice Q. It's a pleasure to ride, but bulky and inconvenient to transport if you're not sitting in it. Rolling resistance is high, but the low position makes it almost immune to wind. With 50 km/h wind in your face, it will slow down, but an upright bicycle will not be rideable. On average, it is slower than a normal bike, but much more comfortable.
This trike is pretty low. Risk of rollover in turns is way overblown in my opinion. But... downhill in the winding mountain roads, due to the aerodynamics, it really wants to go at unsafe speeds. It will do 90 km/h downhill, which is completely nuts. It's up to you to not enter a turn at an unsafe speed. This applies to any vehicle.
It is heavy and slow on climbs, much slower than a normal bike, but it makes up for it on the way down. In fact one problem with the tadpole trike really is that it makes unsafe speeds so much more fun.
There are two front brakes, both capable of lifting the rear wheel unless the trike is loaded with stuff on the rear rack. Applying only one front brake while turning will lift the rear wheel and result in an instant spin. This is very convenient for making U-turns (you also have to fling your body in the proper direction to turn it around).
An unintentional spin could happen, which would cause an accident. However, braking hard will also send you flying over the bars with a normal bike, or roll over a delta trike. Basically, all these vehicles require proper control of the brakes, looking ahead, not braking at the last second, etc. The one thing extra you have to learn on a tadpole trike is to balance the braking between the two front wheels. This is absolutely required and you must learn it. It's not difficult.
The other problem with trikes is the low position makes it hard for drivers to notice you, especially in turns. For example, in this turn, the trike would be hidden by the wall on the right. That's why it has a flag on a pole...