Why the Deutschland class was an awkward commerce raider

Why were the Deutschland class's 11-inch guns a poor fit for commerce raiding?

Their size and complexity burdened a slow raider that needed endurance and escape speed; 8-inch guns could have been more practical.

The large turrets and 11-inch guns were a poor balance for a long-range commerce raider that needed to avoid warships. The mounting imposed weight, hull stress, mechanism size, and ammunition costs while delivering more shell power than was necessary against merchant shipping. Smaller 8-inch guns could have raised the rate of fire and reduced the burden on the hull. The saved displacement could support more fuel or machinery, improving the endurance and escape speed needed whenever enemy cruisers or capital ships appeared. The larger guns offered political prestige and an intimidating paper specification, while the Royal Navy could answer that presence by concentrating several faster cruisers against one raider.