Advantages
There are times when using packet filters makes sense. If the connections require high throughput or the protocols has proprietary technology that makes it not compatibles with other firewall technologies a packet filtering firewall might be in order. Although packet filters have limitations they also have the followings advantage over other firewall technologies.
a.Compatibility packet filters do not modify the packet stream so they works with any protocols.
b.Performance packet filters are very fast since they look only at the headers.
c.Scalability since packets filters are simple it is easy to scale the solution.