Maintenance costs , which are very high for slat-based systems, and Sanitation , which is difficult to achieve with conventional conveyor designs. In turn, the chain is driven by a motor all resulting in additional costs, maintenance AND noise that can diminish the dining experience.
Chains fall off around curves and slats go flying.
Slats disintegrate over time and need to be replaced. Chains break and must be repaired. Chains and channels capture a lot of soil and are difficult to clean. Butz coordinated a major re-design of the kitchen in '83. We ruled that out very quickly.