They have a really low skilsum to start with, will be "too" old soon and their secondary skills, like passing, Jumpshot, driving, handling etc. are horrible.
In Addition the Position shown does not mean a lot, you could buy a really tall PG and turn him into a Center.
Größter Knecht aller Zeiten aka His Excellency aka President for Life aka Field Marshal Al Hadji aka Lord of All the Beasts of the Earth and Fishes of the Seas aka aka Conqueror of the Buzzerbeater Empire in Europe in General and Austria in Particular