Bridges are simpler and less expensive then routers. Bridges make a simple do/don't decision on which packets to send across two segments they connect. Filtering is done based on the destination address of the packet.

If a packet's destination is a station on the same segment where it originated, it is not forwarded. If it is destined for a station on another LAN, it is connected to a different bridge port and forwarded to that port.

Bridge Interconnects LAN segments at the network interface layer level and forwards frames between them.
A bridge performs the function of a MAC relay, and is independent of any higher layer protocol (including the logical link protocol). It provides MAC layer protocol conversion, if required.

A bridge is said to be transparent to IP. That is, when an IP host sends an IP datagram to another host on a network connected by a bridge, it sends the datagram directly to the host and the datagram "crosses" the bridge without the sending IP host being aware of it.