It wouldnt be any cheaper or any easier… doing the 45’s would actually require 1 more bend so if anything, its more work.
Reason for the 90’s is so that it covers the entire brake MC + fits around the Turbo Eblow without any clearance issues.
Notice how it follows the profile of the MC and then leaves room for the turbo outlet… IF you didnt 90 it and did 45 it, it would bring it much closer to the outlet AND the bigger your turbo, the further back that outlet is. So if I did 45 them… they may fit for some people, but wouldnt fit for others. The 90’s ensure it fits no matter what.