An Inventory makes it possible to control what type of rooms and how many you make available to a particular market segment.
Sometimes, a hotel may want to make accessible a certain number of rooms to a particular market, for example: a group of business people who wish to use the hotel's conferencing facilities over a two- or three-day stay. After making this group booking, the hotel can enter into their Inventory book the number of rooms filled. Based on this information they can then adjust their prices for the remaining available rooms in the hotel, if they need to.
Most hotels have an Inventory. In fact, not to have one is a poor business decision, as knowing room availability at all times can be useful when making rapid decisions. When looking to maximise profits, having room availability data at your fingertips can give a hotel a competitive advantage in the marketplace.