Why were the shell keeps better than the square keeps?

Shell keeps were considered superior to square keeps primarily due to their design, which allowed for better defense against attacks. The rounded walls of shell keeps deflected projectiles more effectively and minimized blind spots, while square keeps had corners that could be vulnerable. Additionally, shell keeps often had a smaller footprint, making them easier to defend and less susceptible to siege tactics. Their architectural style also facilitated better use of space for living quarters and storage.