The answer is so simple, it makes perfect sense.
Convertible cars have come a long way over the decades. Cars with removable roofs used to take ages to put up or down, and usually suffered from issues with leaking or fitment. Modern convertibles are much more reliable, but are still slightly less practical than a car with a fixed roof. Hardtop convertibles seem to be the perfect compromise. These types of convertibles offer better security and more sound and weather insulation. On the flip side they add weight, reduce trunk space and cost more money.
Hardtop convertibles may not be worth the added complexity, and even automakers who embraced them such as BMW, are starting to question their usefulness. There is a reason why some of the most expensive convertibles like the Mercedes S-Class and Aston Martin DB11 Volante use classic soft tops instead of folding metal roofs. Speaking to Auto Guide, Aston Martin revealed the real reason why it didn't use a hardtop roof on the DB11 Volante. It could have been any of the reasons we mentioned above - cost, weight, complexity - but the reason is extremely simple, Aston thought it would look ugly.
Julian Nunn, lead exterior designer at Aston Martin Lagonda Ltd, said "Every car that we do in design has to be elegant. It’s got to sit alongside all the other classics. It’s got to be part of the family. If it’s not part of the family we’re not doing something right.” When speaking about convertibles, Nunn explained that the splits and creases in the hardtop mechanism are inappropriate and don't "give you the beauty that you need for these cars.” If you've ever wondered why pricey convertibles like the DB11 Volante don't use a hardtop mechanism, there's your answer.