Many commercial refrigerators and freezers can be fitted with castors instead of fixed legs. Swivel castors let the cabinet be rolled out from a wall or counter, and brakes lock it in place during use. Some units ship with legs and offer castors as an option; others come with both.
The main reason for castors is hygiene. Food debris, spilled liquids and pests collect behind and under heavy cabinets, and a unit that cannot be moved rarely gets cleaned underneath. Rolling it out also gives a technician access to the condenser and the back panel. The trade-offs are a slightly lower stability and a need to check that floors are level, drains are clear, and that power and drain connections allow the unit to move.
A QSR outlet in Chennai might specify castors on all its undercounter units so the night crew can roll them out once a week, sweep and mop behind them, and clean the condenser grilles before rolling them back.