Why use bridging.
Consider a situation where you have a bog standard modem / router provided by your Internet Service Provider.
You’ve just upgraded to the latest and greatest Fibre, EFibre or as it is technically named VDSL connection.
You are getting fantastic speeds but you have a better router there sitting in a box that isn’t VDSL compatible.
This is a perfect reason to use bridging. You use the modem functionality of the modem / router that the Internet Service Provider has given you but you get all the great features of the more expensive router that you already have.
However, let’s say you have a VDSL compatible modem sitting there. You can use this instead of the modem supplied to you by your internet service provider. There are valid arguments that this is actually a more secure solution. However, keep in mind that if you go down this route, your internet Service Provider may not support you if you encounter problems with your Internet connection if you do not have your standard modem to hand.

For more information about how to configure your third party modem to work with Fibre or EFibre look at this site.