TL;DR:The perk is that modules can be custom at your convenience (just follow a specific structure) and be dynamically loaded in the agent

3 components:

server: deploy on attacker machine
agent: deploy on target waiting for command from server
modules: link to the Agent waiting for instruciton from agent

Communication:

server <~> agent (Websocket)
agent <~> modules (IPC)

Agent can be:

dynamically and OTA extended by loading module:
statically built with built-in modules