For some aquariums standing in favorable location (constant room temperature, no drafts, no direct sunlight) the heating of pumps and lamps keeps temperatures at 25 degrees or slightly more. In most cases you should prevent the sagging of the temperature (what about vacation?) with a suitable heater.
Simple controlled heating elements typically save more control technology. For marin aquarium more suitable Titan heaters must be operated by separate control systems, whether the commonly used aquarium computer or special controllers.