You need a broker majorly for the following reasons.
You get only the related options according to your financial conditions. It reduces the threat of unnecessary search footprint on your credit record. Banks and direct lenders reject the application right away, leaving an embarrassing spot on your financial report.
The broker saves a lot of time by doing the mind-boggling part of research for the best deal
It brings to you the cheapest possible deals with lowest interest rates and thus saves your hard-earned money
Brokers take care of all the annoying paperwork for you, which is again a huge help for you as your ignorance of mortgage market makes the procedures more complicated