Is marzipan a very popular candy in Spain?

No, marzipan is a very popular candy in Spain.

Marzipan is a confection made from almond meal, sugar, and egg whites, and is a popular treat in many European countries. While marzipan is sometimes used as an ingredient in Spanish desserts like mazapan de Toledo or empanadillas de mazapan, it is not considered a very popular candy overall in Spain. In Spain, more popular sweet treats include turron (nougat), polvorones (shortbread cookies), and churros (fried dough).